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Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 8572 |
1 files changed, 8572 insertions, 0 deletions
diff --git a/src/select.c b/src/select.c new file mode 100644 index 0000000..1215727 --- /dev/null +++ b/src/select.c @@ -0,0 +1,8572 @@ +/* +** 2001 September 15 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** This file contains C code routines that are called by the parser +** to handle SELECT statements in SQLite. +*/ +#include "sqliteInt.h" + +/* +** An instance of the following object is used to record information about +** how to process the DISTINCT keyword, to simplify passing that information +** into the selectInnerLoop() routine. +*/ +typedef struct DistinctCtx DistinctCtx; +struct DistinctCtx { + u8 isTnct; /* 0: Not distinct. 1: DISTICT 2: DISTINCT and ORDER BY */ + u8 eTnctType; /* One of the WHERE_DISTINCT_* operators */ + int tabTnct; /* Ephemeral table used for DISTINCT processing */ + int addrTnct; /* Address of OP_OpenEphemeral opcode for tabTnct */ +}; + +/* +** An instance of the following object is used to record information about +** the ORDER BY (or GROUP BY) clause of query is being coded. +** +** The aDefer[] array is used by the sorter-references optimization. For +** example, assuming there is no index that can be used for the ORDER BY, +** for the query: +** +** SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10; +** +** it may be more efficient to add just the "a" values to the sorter, and +** retrieve the associated "bigblob" values directly from table t1 as the +** 10 smallest "a" values are extracted from the sorter. +** +** When the sorter-reference optimization is used, there is one entry in the +** aDefer[] array for each database table that may be read as values are +** extracted from the sorter. +*/ +typedef struct SortCtx SortCtx; +struct SortCtx { + ExprList *pOrderBy; /* The ORDER BY (or GROUP BY clause) */ + int nOBSat; /* Number of ORDER BY terms satisfied by indices */ + int iECursor; /* Cursor number for the sorter */ + int regReturn; /* Register holding block-output return address */ + int labelBkOut; /* Start label for the block-output subroutine */ + int addrSortIndex; /* Address of the OP_SorterOpen or OP_OpenEphemeral */ + int labelDone; /* Jump here when done, ex: LIMIT reached */ + int labelOBLopt; /* Jump here when sorter is full */ + u8 sortFlags; /* Zero or more SORTFLAG_* bits */ +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + u8 nDefer; /* Number of valid entries in aDefer[] */ + struct DeferredCsr { + Table *pTab; /* Table definition */ + int iCsr; /* Cursor number for table */ + int nKey; /* Number of PK columns for table pTab (>=1) */ + } aDefer[4]; +#endif + struct RowLoadInfo *pDeferredRowLoad; /* Deferred row loading info or NULL */ +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + int addrPush; /* First instruction to push data into sorter */ + int addrPushEnd; /* Last instruction that pushes data into sorter */ +#endif +}; +#define SORTFLAG_UseSorter 0x01 /* Use SorterOpen instead of OpenEphemeral */ + +/* +** Delete all the content of a Select structure. Deallocate the structure +** itself depending on the value of bFree +** +** If bFree==1, call sqlite3DbFree() on the p object. +** If bFree==0, Leave the first Select object unfreed +*/ +static void clearSelect(sqlite3 *db, Select *p, int bFree){ + assert( db!=0 ); + while( p ){ + Select *pPrior = p->pPrior; + sqlite3ExprListDelete(db, p->pEList); + sqlite3SrcListDelete(db, p->pSrc); + sqlite3ExprDelete(db, p->pWhere); + sqlite3ExprListDelete(db, p->pGroupBy); + sqlite3ExprDelete(db, p->pHaving); + sqlite3ExprListDelete(db, p->pOrderBy); + sqlite3ExprDelete(db, p->pLimit); + if( OK_IF_ALWAYS_TRUE(p->pWith) ) sqlite3WithDelete(db, p->pWith); +#ifndef SQLITE_OMIT_WINDOWFUNC + if( OK_IF_ALWAYS_TRUE(p->pWinDefn) ){ + sqlite3WindowListDelete(db, p->pWinDefn); + } + while( p->pWin ){ + assert( p->pWin->ppThis==&p->pWin ); + sqlite3WindowUnlinkFromSelect(p->pWin); + } +#endif + if( bFree ) sqlite3DbNNFreeNN(db, p); + p = pPrior; + bFree = 1; + } +} + +/* +** Initialize a SelectDest structure. +*/ +void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){ + pDest->eDest = (u8)eDest; + pDest->iSDParm = iParm; + pDest->iSDParm2 = 0; + pDest->zAffSdst = 0; + pDest->iSdst = 0; + pDest->nSdst = 0; +} + + +/* +** Allocate a new Select structure and return a pointer to that +** structure. +*/ +Select *sqlite3SelectNew( + Parse *pParse, /* Parsing context */ + ExprList *pEList, /* which columns to include in the result */ + SrcList *pSrc, /* the FROM clause -- which tables to scan */ + Expr *pWhere, /* the WHERE clause */ + ExprList *pGroupBy, /* the GROUP BY clause */ + Expr *pHaving, /* the HAVING clause */ + ExprList *pOrderBy, /* the ORDER BY clause */ + u32 selFlags, /* Flag parameters, such as SF_Distinct */ + Expr *pLimit /* LIMIT value. NULL means not used */ +){ + Select *pNew, *pAllocated; + Select standin; + pAllocated = pNew = sqlite3DbMallocRawNN(pParse->db, sizeof(*pNew) ); + if( pNew==0 ){ + assert( pParse->db->mallocFailed ); + pNew = &standin; + } + if( pEList==0 ){ + pEList = sqlite3ExprListAppend(pParse, 0, + sqlite3Expr(pParse->db,TK_ASTERISK,0)); + } + pNew->pEList = pEList; + pNew->op = TK_SELECT; + pNew->selFlags = selFlags; + pNew->iLimit = 0; + pNew->iOffset = 0; + pNew->selId = ++pParse->nSelect; + pNew->addrOpenEphm[0] = -1; + pNew->addrOpenEphm[1] = -1; + pNew->nSelectRow = 0; + if( pSrc==0 ) pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*pSrc)); + pNew->pSrc = pSrc; + pNew->pWhere = pWhere; + pNew->pGroupBy = pGroupBy; + pNew->pHaving = pHaving; + pNew->pOrderBy = pOrderBy; + pNew->pPrior = 0; + pNew->pNext = 0; + pNew->pLimit = pLimit; + pNew->pWith = 0; +#ifndef SQLITE_OMIT_WINDOWFUNC + pNew->pWin = 0; + pNew->pWinDefn = 0; +#endif + if( pParse->db->mallocFailed ) { + clearSelect(pParse->db, pNew, pNew!=&standin); + pAllocated = 0; + }else{ + assert( pNew->pSrc!=0 || pParse->nErr>0 ); + } + return pAllocated; +} + + +/* +** Delete the given Select structure and all of its substructures. +*/ +void sqlite3SelectDelete(sqlite3 *db, Select *p){ + if( OK_IF_ALWAYS_TRUE(p) ) clearSelect(db, p, 1); +} +void sqlite3SelectDeleteGeneric(sqlite3 *db, void *p){ + if( ALWAYS(p) ) clearSelect(db, (Select*)p, 1); +} + +/* +** Return a pointer to the right-most SELECT statement in a compound. +*/ +static Select *findRightmost(Select *p){ + while( p->pNext ) p = p->pNext; + return p; +} + +/* +** Given 1 to 3 identifiers preceding the JOIN keyword, determine the +** type of join. Return an integer constant that expresses that type +** in terms of the following bit values: +** +** JT_INNER +** JT_CROSS +** JT_OUTER +** JT_NATURAL +** JT_LEFT +** JT_RIGHT +** +** A full outer join is the combination of JT_LEFT and JT_RIGHT. +** +** If an illegal or unsupported join type is seen, then still return +** a join type, but put an error in the pParse structure. +** +** These are the valid join types: +** +** +** pA pB pC Return Value +** ------- ----- ----- ------------ +** CROSS - - JT_CROSS +** INNER - - JT_INNER +** LEFT - - JT_LEFT|JT_OUTER +** LEFT OUTER - JT_LEFT|JT_OUTER +** RIGHT - - JT_RIGHT|JT_OUTER +** RIGHT OUTER - JT_RIGHT|JT_OUTER +** FULL - - JT_LEFT|JT_RIGHT|JT_OUTER +** FULL OUTER - JT_LEFT|JT_RIGHT|JT_OUTER +** NATURAL INNER - JT_NATURAL|JT_INNER +** NATURAL LEFT - JT_NATURAL|JT_LEFT|JT_OUTER +** NATURAL LEFT OUTER JT_NATURAL|JT_LEFT|JT_OUTER +** NATURAL RIGHT - JT_NATURAL|JT_RIGHT|JT_OUTER +** NATURAL RIGHT OUTER JT_NATURAL|JT_RIGHT|JT_OUTER +** NATURAL FULL - JT_NATURAL|JT_LEFT|JT_RIGHT +** NATURAL FULL OUTER JT_NATRUAL|JT_LEFT|JT_RIGHT +** +** To preserve historical compatibly, SQLite also accepts a variety +** of other non-standard and in many cases nonsensical join types. +** This routine makes as much sense at it can from the nonsense join +** type and returns a result. Examples of accepted nonsense join types +** include but are not limited to: +** +** INNER CROSS JOIN -> same as JOIN +** NATURAL CROSS JOIN -> same as NATURAL JOIN +** OUTER LEFT JOIN -> same as LEFT JOIN +** LEFT NATURAL JOIN -> same as NATURAL LEFT JOIN +** LEFT RIGHT JOIN -> same as FULL JOIN +** RIGHT OUTER FULL JOIN -> same as FULL JOIN +** CROSS CROSS CROSS JOIN -> same as JOIN +** +** The only restrictions on the join type name are: +** +** * "INNER" cannot appear together with "OUTER", "LEFT", "RIGHT", +** or "FULL". +** +** * "CROSS" cannot appear together with "OUTER", "LEFT", "RIGHT, +** or "FULL". +** +** * If "OUTER" is present then there must also be one of +** "LEFT", "RIGHT", or "FULL" +*/ +int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){ + int jointype = 0; + Token *apAll[3]; + Token *p; + /* 0123456789 123456789 123456789 123 */ + static const char zKeyText[] = "naturaleftouterightfullinnercross"; + static const struct { + u8 i; /* Beginning of keyword text in zKeyText[] */ + u8 nChar; /* Length of the keyword in characters */ + u8 code; /* Join type mask */ + } aKeyword[] = { + /* (0) natural */ { 0, 7, JT_NATURAL }, + /* (1) left */ { 6, 4, JT_LEFT|JT_OUTER }, + /* (2) outer */ { 10, 5, JT_OUTER }, + /* (3) right */ { 14, 5, JT_RIGHT|JT_OUTER }, + /* (4) full */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER }, + /* (5) inner */ { 23, 5, JT_INNER }, + /* (6) cross */ { 28, 5, JT_INNER|JT_CROSS }, + }; + int i, j; + apAll[0] = pA; + apAll[1] = pB; + apAll[2] = pC; + for(i=0; i<3 && apAll[i]; i++){ + p = apAll[i]; + for(j=0; j<ArraySize(aKeyword); j++){ + if( p->n==aKeyword[j].nChar + && sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){ + jointype |= aKeyword[j].code; + break; + } + } + testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 ); + if( j>=ArraySize(aKeyword) ){ + jointype |= JT_ERROR; + break; + } + } + if( + (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) || + (jointype & JT_ERROR)!=0 || + (jointype & (JT_OUTER|JT_LEFT|JT_RIGHT))==JT_OUTER + ){ + const char *zSp1 = " "; + const char *zSp2 = " "; + if( pB==0 ){ zSp1++; } + if( pC==0 ){ zSp2++; } + sqlite3ErrorMsg(pParse, "unknown join type: " + "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC); + jointype = JT_INNER; + } + return jointype; +} + +/* +** Return the index of a column in a table. Return -1 if the column +** is not contained in the table. +*/ +int sqlite3ColumnIndex(Table *pTab, const char *zCol){ + int i; + u8 h = sqlite3StrIHash(zCol); + Column *pCol; + for(pCol=pTab->aCol, i=0; i<pTab->nCol; pCol++, i++){ + if( pCol->hName==h && sqlite3StrICmp(pCol->zCnName, zCol)==0 ) return i; + } + return -1; +} + +/* +** Mark a subquery result column as having been used. +*/ +void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){ + assert( pItem!=0 ); + assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->pSelect) ); + if( pItem->fg.isNestedFrom ){ + ExprList *pResults; + assert( pItem->pSelect!=0 ); + pResults = pItem->pSelect->pEList; + assert( pResults!=0 ); + assert( iCol>=0 && iCol<pResults->nExpr ); + pResults->a[iCol].fg.bUsed = 1; + } +} + +/* +** Search the tables iStart..iEnd (inclusive) in pSrc, looking for a +** table that has a column named zCol. The search is left-to-right. +** The first match found is returned. +** +** When found, set *piTab and *piCol to the table index and column index +** of the matching column and return TRUE. +** +** If not found, return FALSE. +*/ +static int tableAndColumnIndex( + SrcList *pSrc, /* Array of tables to search */ + int iStart, /* First member of pSrc->a[] to check */ + int iEnd, /* Last member of pSrc->a[] to check */ + const char *zCol, /* Name of the column we are looking for */ + int *piTab, /* Write index of pSrc->a[] here */ + int *piCol, /* Write index of pSrc->a[*piTab].pTab->aCol[] here */ + int bIgnoreHidden /* Ignore hidden columns */ +){ + int i; /* For looping over tables in pSrc */ + int iCol; /* Index of column matching zCol */ + + assert( iEnd<pSrc->nSrc ); + assert( iStart>=0 ); + assert( (piTab==0)==(piCol==0) ); /* Both or neither are NULL */ + + for(i=iStart; i<=iEnd; i++){ + iCol = sqlite3ColumnIndex(pSrc->a[i].pTab, zCol); + if( iCol>=0 + && (bIgnoreHidden==0 || IsHiddenColumn(&pSrc->a[i].pTab->aCol[iCol])==0) + ){ + if( piTab ){ + sqlite3SrcItemColumnUsed(&pSrc->a[i], iCol); + *piTab = i; + *piCol = iCol; + } + return 1; + } + } + return 0; +} + +/* +** Set the EP_OuterON property on all terms of the given expression. +** And set the Expr.w.iJoin to iTable for every term in the +** expression. +** +** The EP_OuterON property is used on terms of an expression to tell +** the OUTER JOIN processing logic that this term is part of the +** join restriction specified in the ON or USING clause and not a part +** of the more general WHERE clause. These terms are moved over to the +** WHERE clause during join processing but we need to remember that they +** originated in the ON or USING clause. +** +** The Expr.w.iJoin tells the WHERE clause processing that the +** expression depends on table w.iJoin even if that table is not +** explicitly mentioned in the expression. That information is needed +** for cases like this: +** +** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5 +** +** The where clause needs to defer the handling of the t1.x=5 +** term until after the t2 loop of the join. In that way, a +** NULL t2 row will be inserted whenever t1.x!=5. If we do not +** defer the handling of t1.x=5, it will be processed immediately +** after the t1 loop and rows with t1.x!=5 will never appear in +** the output, which is incorrect. +*/ +void sqlite3SetJoinExpr(Expr *p, int iTable, u32 joinFlag){ + assert( joinFlag==EP_OuterON || joinFlag==EP_InnerON ); + while( p ){ + ExprSetProperty(p, joinFlag); + assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) ); + ExprSetVVAProperty(p, EP_NoReduce); + p->w.iJoin = iTable; + if( p->op==TK_FUNCTION ){ + assert( ExprUseXList(p) ); + if( p->x.pList ){ + int i; + for(i=0; i<p->x.pList->nExpr; i++){ + sqlite3SetJoinExpr(p->x.pList->a[i].pExpr, iTable, joinFlag); + } + } + } + sqlite3SetJoinExpr(p->pLeft, iTable, joinFlag); + p = p->pRight; + } +} + +/* Undo the work of sqlite3SetJoinExpr(). This is used when a LEFT JOIN +** is simplified into an ordinary JOIN, and when an ON expression is +** "pushed down" into the WHERE clause of a subquery. +** +** Convert every term that is marked with EP_OuterON and w.iJoin==iTable into +** an ordinary term that omits the EP_OuterON mark. Or if iTable<0, then +** just clear every EP_OuterON and EP_InnerON mark from the expression tree. +** +** If nullable is true, that means that Expr p might evaluate to NULL even +** if it is a reference to a NOT NULL column. This can happen, for example, +** if the table that p references is on the left side of a RIGHT JOIN. +** If nullable is true, then take care to not remove the EP_CanBeNull bit. +** See forum thread https://sqlite.org/forum/forumpost/b40696f50145d21c +*/ +static void unsetJoinExpr(Expr *p, int iTable, int nullable){ + while( p ){ + if( iTable<0 || (ExprHasProperty(p, EP_OuterON) && p->w.iJoin==iTable) ){ + ExprClearProperty(p, EP_OuterON|EP_InnerON); + if( iTable>=0 ) ExprSetProperty(p, EP_InnerON); + } + if( p->op==TK_COLUMN && p->iTable==iTable && !nullable ){ + ExprClearProperty(p, EP_CanBeNull); + } + if( p->op==TK_FUNCTION ){ + assert( ExprUseXList(p) ); + assert( p->pLeft==0 ); + if( p->x.pList ){ + int i; + for(i=0; i<p->x.pList->nExpr; i++){ + unsetJoinExpr(p->x.pList->a[i].pExpr, iTable, nullable); + } + } + } + unsetJoinExpr(p->pLeft, iTable, nullable); + p = p->pRight; + } +} + +/* +** This routine processes the join information for a SELECT statement. +** +** * A NATURAL join is converted into a USING join. After that, we +** do not need to be concerned with NATURAL joins and we only have +** think about USING joins. +** +** * ON and USING clauses result in extra terms being added to the +** WHERE clause to enforce the specified constraints. The extra +** WHERE clause terms will be tagged with EP_OuterON or +** EP_InnerON so that we know that they originated in ON/USING. +** +** The terms of a FROM clause are contained in the Select.pSrc structure. +** The left most table is the first entry in Select.pSrc. The right-most +** table is the last entry. The join operator is held in the entry to +** the right. Thus entry 1 contains the join operator for the join between +** entries 0 and 1. Any ON or USING clauses associated with the join are +** also attached to the right entry. +** +** This routine returns the number of errors encountered. +*/ +static int sqlite3ProcessJoin(Parse *pParse, Select *p){ + SrcList *pSrc; /* All tables in the FROM clause */ + int i, j; /* Loop counters */ + SrcItem *pLeft; /* Left table being joined */ + SrcItem *pRight; /* Right table being joined */ + + pSrc = p->pSrc; + pLeft = &pSrc->a[0]; + pRight = &pLeft[1]; + for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){ + Table *pRightTab = pRight->pTab; + u32 joinType; + + if( NEVER(pLeft->pTab==0 || pRightTab==0) ) continue; + joinType = (pRight->fg.jointype & JT_OUTER)!=0 ? EP_OuterON : EP_InnerON; + + /* If this is a NATURAL join, synthesize an appropriate USING clause + ** to specify which columns should be joined. + */ + if( pRight->fg.jointype & JT_NATURAL ){ + IdList *pUsing = 0; + if( pRight->fg.isUsing || pRight->u3.pOn ){ + sqlite3ErrorMsg(pParse, "a NATURAL join may not have " + "an ON or USING clause", 0); + return 1; + } + for(j=0; j<pRightTab->nCol; j++){ + char *zName; /* Name of column in the right table */ + + if( IsHiddenColumn(&pRightTab->aCol[j]) ) continue; + zName = pRightTab->aCol[j].zCnName; + if( tableAndColumnIndex(pSrc, 0, i, zName, 0, 0, 1) ){ + pUsing = sqlite3IdListAppend(pParse, pUsing, 0); + if( pUsing ){ + assert( pUsing->nId>0 ); + assert( pUsing->a[pUsing->nId-1].zName==0 ); + pUsing->a[pUsing->nId-1].zName = sqlite3DbStrDup(pParse->db, zName); + } + } + } + if( pUsing ){ + pRight->fg.isUsing = 1; + pRight->fg.isSynthUsing = 1; + pRight->u3.pUsing = pUsing; + } + if( pParse->nErr ) return 1; + } + + /* Create extra terms on the WHERE clause for each column named + ** in the USING clause. Example: If the two tables to be joined are + ** A and B and the USING clause names X, Y, and Z, then add this + ** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z + ** Report an error if any column mentioned in the USING clause is + ** not contained in both tables to be joined. + */ + if( pRight->fg.isUsing ){ + IdList *pList = pRight->u3.pUsing; + sqlite3 *db = pParse->db; + assert( pList!=0 ); + for(j=0; j<pList->nId; j++){ + char *zName; /* Name of the term in the USING clause */ + int iLeft; /* Table on the left with matching column name */ + int iLeftCol; /* Column number of matching column on the left */ + int iRightCol; /* Column number of matching column on the right */ + Expr *pE1; /* Reference to the column on the LEFT of the join */ + Expr *pE2; /* Reference to the column on the RIGHT of the join */ + Expr *pEq; /* Equality constraint. pE1 == pE2 */ + + zName = pList->a[j].zName; + iRightCol = sqlite3ColumnIndex(pRightTab, zName); + if( iRightCol<0 + || tableAndColumnIndex(pSrc, 0, i, zName, &iLeft, &iLeftCol, + pRight->fg.isSynthUsing)==0 + ){ + sqlite3ErrorMsg(pParse, "cannot join using column %s - column " + "not present in both tables", zName); + return 1; + } + pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol); + sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol); + if( (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){ + /* This branch runs if the query contains one or more RIGHT or FULL + ** JOINs. If only a single table on the left side of this join + ** contains the zName column, then this branch is a no-op. + ** But if there are two or more tables on the left side + ** of the join, construct a coalesce() function that gathers all + ** such tables. Raise an error if more than one of those references + ** to zName is not also within a prior USING clause. + ** + ** We really ought to raise an error if there are two or more + ** non-USING references to zName on the left of an INNER or LEFT + ** JOIN. But older versions of SQLite do not do that, so we avoid + ** adding a new error so as to not break legacy applications. + */ + ExprList *pFuncArgs = 0; /* Arguments to the coalesce() */ + static const Token tkCoalesce = { "coalesce", 8 }; + while( tableAndColumnIndex(pSrc, iLeft+1, i, zName, &iLeft, &iLeftCol, + pRight->fg.isSynthUsing)!=0 ){ + if( pSrc->a[iLeft].fg.isUsing==0 + || sqlite3IdListIndex(pSrc->a[iLeft].u3.pUsing, zName)<0 + ){ + sqlite3ErrorMsg(pParse, "ambiguous reference to %s in USING()", + zName); + break; + } + pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1); + pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol); + sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol); + } + if( pFuncArgs ){ + pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1); + pE1 = sqlite3ExprFunction(pParse, pFuncArgs, &tkCoalesce, 0); + } + } + pE2 = sqlite3CreateColumnExpr(db, pSrc, i+1, iRightCol); + sqlite3SrcItemColumnUsed(pRight, iRightCol); + pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2); + assert( pE2!=0 || pEq==0 ); + if( pEq ){ + ExprSetProperty(pEq, joinType); + assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) ); + ExprSetVVAProperty(pEq, EP_NoReduce); + pEq->w.iJoin = pE2->iTable; + } + p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pEq); + } + } + + /* Add the ON clause to the end of the WHERE clause, connected by + ** an AND operator. + */ + else if( pRight->u3.pOn ){ + sqlite3SetJoinExpr(pRight->u3.pOn, pRight->iCursor, joinType); + p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pRight->u3.pOn); + pRight->u3.pOn = 0; + pRight->fg.isOn = 1; + } + } + return 0; +} + +/* +** An instance of this object holds information (beyond pParse and pSelect) +** needed to load the next result row that is to be added to the sorter. +*/ +typedef struct RowLoadInfo RowLoadInfo; +struct RowLoadInfo { + int regResult; /* Store results in array of registers here */ + u8 ecelFlags; /* Flag argument to ExprCodeExprList() */ +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + ExprList *pExtra; /* Extra columns needed by sorter refs */ + int regExtraResult; /* Where to load the extra columns */ +#endif +}; + +/* +** This routine does the work of loading query data into an array of +** registers so that it can be added to the sorter. +*/ +static void innerLoopLoadRow( + Parse *pParse, /* Statement under construction */ + Select *pSelect, /* The query being coded */ + RowLoadInfo *pInfo /* Info needed to complete the row load */ +){ + sqlite3ExprCodeExprList(pParse, pSelect->pEList, pInfo->regResult, + 0, pInfo->ecelFlags); +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + if( pInfo->pExtra ){ + sqlite3ExprCodeExprList(pParse, pInfo->pExtra, pInfo->regExtraResult, 0, 0); + sqlite3ExprListDelete(pParse->db, pInfo->pExtra); + } +#endif +} + +/* +** Code the OP_MakeRecord instruction that generates the entry to be +** added into the sorter. +** +** Return the register in which the result is stored. +*/ +static int makeSorterRecord( + Parse *pParse, + SortCtx *pSort, + Select *pSelect, + int regBase, + int nBase +){ + int nOBSat = pSort->nOBSat; + Vdbe *v = pParse->pVdbe; + int regOut = ++pParse->nMem; + if( pSort->pDeferredRowLoad ){ + innerLoopLoadRow(pParse, pSelect, pSort->pDeferredRowLoad); + } + sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat, regOut); + return regOut; +} + +/* +** Generate code that will push the record in registers regData +** through regData+nData-1 onto the sorter. +*/ +static void pushOntoSorter( + Parse *pParse, /* Parser context */ + SortCtx *pSort, /* Information about the ORDER BY clause */ + Select *pSelect, /* The whole SELECT statement */ + int regData, /* First register holding data to be sorted */ + int regOrigData, /* First register holding data before packing */ + int nData, /* Number of elements in the regData data array */ + int nPrefixReg /* No. of reg prior to regData available for use */ +){ + Vdbe *v = pParse->pVdbe; /* Stmt under construction */ + int bSeq = ((pSort->sortFlags & SORTFLAG_UseSorter)==0); + int nExpr = pSort->pOrderBy->nExpr; /* No. of ORDER BY terms */ + int nBase = nExpr + bSeq + nData; /* Fields in sorter record */ + int regBase; /* Regs for sorter record */ + int regRecord = 0; /* Assembled sorter record */ + int nOBSat = pSort->nOBSat; /* ORDER BY terms to skip */ + int op; /* Opcode to add sorter record to sorter */ + int iLimit; /* LIMIT counter */ + int iSkip = 0; /* End of the sorter insert loop */ + + assert( bSeq==0 || bSeq==1 ); + + /* Three cases: + ** (1) The data to be sorted has already been packed into a Record + ** by a prior OP_MakeRecord. In this case nData==1 and regData + ** will be completely unrelated to regOrigData. + ** (2) All output columns are included in the sort record. In that + ** case regData==regOrigData. + ** (3) Some output columns are omitted from the sort record due to + ** the SQLITE_ENABLE_SORTER_REFERENCES optimization, or due to the + ** SQLITE_ECEL_OMITREF optimization, or due to the + ** SortCtx.pDeferredRowLoad optimization. In any of these cases + ** regOrigData is 0 to prevent this routine from trying to copy + ** values that might not yet exist. + */ + assert( nData==1 || regData==regOrigData || regOrigData==0 ); + +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + pSort->addrPush = sqlite3VdbeCurrentAddr(v); +#endif + + if( nPrefixReg ){ + assert( nPrefixReg==nExpr+bSeq ); + regBase = regData - nPrefixReg; + }else{ + regBase = pParse->nMem + 1; + pParse->nMem += nBase; + } + assert( pSelect->iOffset==0 || pSelect->iLimit!=0 ); + iLimit = pSelect->iOffset ? pSelect->iOffset+1 : pSelect->iLimit; + pSort->labelDone = sqlite3VdbeMakeLabel(pParse); + sqlite3ExprCodeExprList(pParse, pSort->pOrderBy, regBase, regOrigData, + SQLITE_ECEL_DUP | (regOrigData? SQLITE_ECEL_REF : 0)); + if( bSeq ){ + sqlite3VdbeAddOp2(v, OP_Sequence, pSort->iECursor, regBase+nExpr); + } + if( nPrefixReg==0 && nData>0 ){ + sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+bSeq, nData); + } + if( nOBSat>0 ){ + int regPrevKey; /* The first nOBSat columns of the previous row */ + int addrFirst; /* Address of the OP_IfNot opcode */ + int addrJmp; /* Address of the OP_Jump opcode */ + VdbeOp *pOp; /* Opcode that opens the sorter */ + int nKey; /* Number of sorting key columns, including OP_Sequence */ + KeyInfo *pKI; /* Original KeyInfo on the sorter table */ + + regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase); + regPrevKey = pParse->nMem+1; + pParse->nMem += pSort->nOBSat; + nKey = nExpr - pSort->nOBSat + bSeq; + if( bSeq ){ + addrFirst = sqlite3VdbeAddOp1(v, OP_IfNot, regBase+nExpr); + }else{ + addrFirst = sqlite3VdbeAddOp1(v, OP_SequenceTest, pSort->iECursor); + } + VdbeCoverage(v); + sqlite3VdbeAddOp3(v, OP_Compare, regPrevKey, regBase, pSort->nOBSat); + pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex); + if( pParse->db->mallocFailed ) return; + pOp->p2 = nKey + nData; + pKI = pOp->p4.pKeyInfo; + memset(pKI->aSortFlags, 0, pKI->nKeyField); /* Makes OP_Jump testable */ + sqlite3VdbeChangeP4(v, -1, (char*)pKI, P4_KEYINFO); + testcase( pKI->nAllField > pKI->nKeyField+2 ); + pOp->p4.pKeyInfo = sqlite3KeyInfoFromExprList(pParse,pSort->pOrderBy,nOBSat, + pKI->nAllField-pKI->nKeyField-1); + pOp = 0; /* Ensure pOp not used after sqlite3VdbeAddOp3() */ + addrJmp = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp3(v, OP_Jump, addrJmp+1, 0, addrJmp+1); VdbeCoverage(v); + pSort->labelBkOut = sqlite3VdbeMakeLabel(pParse); + pSort->regReturn = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut); + sqlite3VdbeAddOp1(v, OP_ResetSorter, pSort->iECursor); + if( iLimit ){ + sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, pSort->labelDone); + VdbeCoverage(v); + } + sqlite3VdbeJumpHere(v, addrFirst); + sqlite3ExprCodeMove(pParse, regBase, regPrevKey, pSort->nOBSat); + sqlite3VdbeJumpHere(v, addrJmp); + } + if( iLimit ){ + /* At this point the values for the new sorter entry are stored + ** in an array of registers. They need to be composed into a record + ** and inserted into the sorter if either (a) there are currently + ** less than LIMIT+OFFSET items or (b) the new record is smaller than + ** the largest record currently in the sorter. If (b) is true and there + ** are already LIMIT+OFFSET items in the sorter, delete the largest + ** entry before inserting the new one. This way there are never more + ** than LIMIT+OFFSET items in the sorter. + ** + ** If the new record does not need to be inserted into the sorter, + ** jump to the next iteration of the loop. If the pSort->labelOBLopt + ** value is not zero, then it is a label of where to jump. Otherwise, + ** just bypass the row insert logic. See the header comment on the + ** sqlite3WhereOrderByLimitOptLabel() function for additional info. + */ + int iCsr = pSort->iECursor; + sqlite3VdbeAddOp2(v, OP_IfNotZero, iLimit, sqlite3VdbeCurrentAddr(v)+4); + VdbeCoverage(v); + sqlite3VdbeAddOp2(v, OP_Last, iCsr, 0); + iSkip = sqlite3VdbeAddOp4Int(v, OP_IdxLE, + iCsr, 0, regBase+nOBSat, nExpr-nOBSat); + VdbeCoverage(v); + sqlite3VdbeAddOp1(v, OP_Delete, iCsr); + } + if( regRecord==0 ){ + regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase); + } + if( pSort->sortFlags & SORTFLAG_UseSorter ){ + op = OP_SorterInsert; + }else{ + op = OP_IdxInsert; + } + sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord, + regBase+nOBSat, nBase-nOBSat); + if( iSkip ){ + sqlite3VdbeChangeP2(v, iSkip, + pSort->labelOBLopt ? pSort->labelOBLopt : sqlite3VdbeCurrentAddr(v)); + } +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + pSort->addrPushEnd = sqlite3VdbeCurrentAddr(v)-1; +#endif +} + +/* +** Add code to implement the OFFSET +*/ +static void codeOffset( + Vdbe *v, /* Generate code into this VM */ + int iOffset, /* Register holding the offset counter */ + int iContinue /* Jump here to skip the current record */ +){ + if( iOffset>0 ){ + sqlite3VdbeAddOp3(v, OP_IfPos, iOffset, iContinue, 1); VdbeCoverage(v); + VdbeComment((v, "OFFSET")); + } +} + +/* +** Add code that will check to make sure the array of registers starting at +** iMem form a distinct entry. This is used by both "SELECT DISTINCT ..." and +** distinct aggregates ("SELECT count(DISTINCT <expr>) ..."). Three strategies +** are available. Which is used depends on the value of parameter eTnctType, +** as follows: +** +** WHERE_DISTINCT_UNORDERED/WHERE_DISTINCT_NOOP: +** Build an ephemeral table that contains all entries seen before and +** skip entries which have been seen before. +** +** Parameter iTab is the cursor number of an ephemeral table that must +** be opened before the VM code generated by this routine is executed. +** The ephemeral cursor table is queried for a record identical to the +** record formed by the current array of registers. If one is found, +** jump to VM address addrRepeat. Otherwise, insert a new record into +** the ephemeral cursor and proceed. +** +** The returned value in this case is a copy of parameter iTab. +** +** WHERE_DISTINCT_ORDERED: +** In this case rows are being delivered sorted order. The ephemeral +** table is not required. Instead, the current set of values +** is compared against previous row. If they match, the new row +** is not distinct and control jumps to VM address addrRepeat. Otherwise, +** the VM program proceeds with processing the new row. +** +** The returned value in this case is the register number of the first +** in an array of registers used to store the previous result row so that +** it can be compared to the next. The caller must ensure that this +** register is initialized to NULL. (The fixDistinctOpenEph() routine +** will take care of this initialization.) +** +** WHERE_DISTINCT_UNIQUE: +** In this case it has already been determined that the rows are distinct. +** No special action is required. The return value is zero. +** +** Parameter pEList is the list of expressions used to generated the +** contents of each row. It is used by this routine to determine (a) +** how many elements there are in the array of registers and (b) the +** collation sequences that should be used for the comparisons if +** eTnctType is WHERE_DISTINCT_ORDERED. +*/ +static int codeDistinct( + Parse *pParse, /* Parsing and code generating context */ + int eTnctType, /* WHERE_DISTINCT_* value */ + int iTab, /* A sorting index used to test for distinctness */ + int addrRepeat, /* Jump to here if not distinct */ + ExprList *pEList, /* Expression for each element */ + int regElem /* First element */ +){ + int iRet = 0; + int nResultCol = pEList->nExpr; + Vdbe *v = pParse->pVdbe; + + switch( eTnctType ){ + case WHERE_DISTINCT_ORDERED: { + int i; + int iJump; /* Jump destination */ + int regPrev; /* Previous row content */ + + /* Allocate space for the previous row */ + iRet = regPrev = pParse->nMem+1; + pParse->nMem += nResultCol; + + iJump = sqlite3VdbeCurrentAddr(v) + nResultCol; + for(i=0; i<nResultCol; i++){ + CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr); + if( i<nResultCol-1 ){ + sqlite3VdbeAddOp3(v, OP_Ne, regElem+i, iJump, regPrev+i); + VdbeCoverage(v); + }else{ + sqlite3VdbeAddOp3(v, OP_Eq, regElem+i, addrRepeat, regPrev+i); + VdbeCoverage(v); + } + sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ); + sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); + } + assert( sqlite3VdbeCurrentAddr(v)==iJump || pParse->db->mallocFailed ); + sqlite3VdbeAddOp3(v, OP_Copy, regElem, regPrev, nResultCol-1); + break; + } + + case WHERE_DISTINCT_UNIQUE: { + /* nothing to do */ + break; + } + + default: { + int r1 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, regElem, nResultCol); + VdbeCoverage(v); + sqlite3VdbeAddOp3(v, OP_MakeRecord, regElem, nResultCol, r1); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iTab, r1, regElem, nResultCol); + sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT); + sqlite3ReleaseTempReg(pParse, r1); + iRet = iTab; + break; + } + } + + return iRet; +} + +/* +** This routine runs after codeDistinct(). It makes necessary +** adjustments to the OP_OpenEphemeral opcode that the codeDistinct() +** routine made use of. This processing must be done separately since +** sometimes codeDistinct is called before the OP_OpenEphemeral is actually +** laid down. +** +** WHERE_DISTINCT_NOOP: +** WHERE_DISTINCT_UNORDERED: +** +** No adjustments necessary. This function is a no-op. +** +** WHERE_DISTINCT_UNIQUE: +** +** The ephemeral table is not needed. So change the +** OP_OpenEphemeral opcode into an OP_Noop. +** +** WHERE_DISTINCT_ORDERED: +** +** The ephemeral table is not needed. But we do need register +** iVal to be initialized to NULL. So change the OP_OpenEphemeral +** into an OP_Null on the iVal register. +*/ +static void fixDistinctOpenEph( + Parse *pParse, /* Parsing and code generating context */ + int eTnctType, /* WHERE_DISTINCT_* value */ + int iVal, /* Value returned by codeDistinct() */ + int iOpenEphAddr /* Address of OP_OpenEphemeral instruction for iTab */ +){ + if( pParse->nErr==0 + && (eTnctType==WHERE_DISTINCT_UNIQUE || eTnctType==WHERE_DISTINCT_ORDERED) + ){ + Vdbe *v = pParse->pVdbe; + sqlite3VdbeChangeToNoop(v, iOpenEphAddr); + if( sqlite3VdbeGetOp(v, iOpenEphAddr+1)->opcode==OP_Explain ){ + sqlite3VdbeChangeToNoop(v, iOpenEphAddr+1); + } + if( eTnctType==WHERE_DISTINCT_ORDERED ){ + /* Change the OP_OpenEphemeral to an OP_Null that sets the MEM_Cleared + ** bit on the first register of the previous value. This will cause the + ** OP_Ne added in codeDistinct() to always fail on the first iteration of + ** the loop even if the first row is all NULLs. */ + VdbeOp *pOp = sqlite3VdbeGetOp(v, iOpenEphAddr); + pOp->opcode = OP_Null; + pOp->p1 = 1; + pOp->p2 = iVal; + } + } +} + +#ifdef SQLITE_ENABLE_SORTER_REFERENCES +/* +** This function is called as part of inner-loop generation for a SELECT +** statement with an ORDER BY that is not optimized by an index. It +** determines the expressions, if any, that the sorter-reference +** optimization should be used for. The sorter-reference optimization +** is used for SELECT queries like: +** +** SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10 +** +** If the optimization is used for expression "bigblob", then instead of +** storing values read from that column in the sorter records, the PK of +** the row from table t1 is stored instead. Then, as records are extracted from +** the sorter to return to the user, the required value of bigblob is +** retrieved directly from table t1. If the values are very large, this +** can be more efficient than storing them directly in the sorter records. +** +** The ExprList_item.fg.bSorterRef flag is set for each expression in pEList +** for which the sorter-reference optimization should be enabled. +** Additionally, the pSort->aDefer[] array is populated with entries +** for all cursors required to evaluate all selected expressions. Finally. +** output variable (*ppExtra) is set to an expression list containing +** expressions for all extra PK values that should be stored in the +** sorter records. +*/ +static void selectExprDefer( + Parse *pParse, /* Leave any error here */ + SortCtx *pSort, /* Sorter context */ + ExprList *pEList, /* Expressions destined for sorter */ + ExprList **ppExtra /* Expressions to append to sorter record */ +){ + int i; + int nDefer = 0; + ExprList *pExtra = 0; + for(i=0; i<pEList->nExpr; i++){ + struct ExprList_item *pItem = &pEList->a[i]; + if( pItem->u.x.iOrderByCol==0 ){ + Expr *pExpr = pItem->pExpr; + Table *pTab; + if( pExpr->op==TK_COLUMN + && pExpr->iColumn>=0 + && ALWAYS( ExprUseYTab(pExpr) ) + && (pTab = pExpr->y.pTab)!=0 + && IsOrdinaryTable(pTab) + && (pTab->aCol[pExpr->iColumn].colFlags & COLFLAG_SORTERREF)!=0 + ){ + int j; + for(j=0; j<nDefer; j++){ + if( pSort->aDefer[j].iCsr==pExpr->iTable ) break; + } + if( j==nDefer ){ + if( nDefer==ArraySize(pSort->aDefer) ){ + continue; + }else{ + int nKey = 1; + int k; + Index *pPk = 0; + if( !HasRowid(pTab) ){ + pPk = sqlite3PrimaryKeyIndex(pTab); + nKey = pPk->nKeyCol; + } + for(k=0; k<nKey; k++){ + Expr *pNew = sqlite3PExpr(pParse, TK_COLUMN, 0, 0); + if( pNew ){ + pNew->iTable = pExpr->iTable; + assert( ExprUseYTab(pNew) ); + pNew->y.pTab = pExpr->y.pTab; + pNew->iColumn = pPk ? pPk->aiColumn[k] : -1; + pExtra = sqlite3ExprListAppend(pParse, pExtra, pNew); + } + } + pSort->aDefer[nDefer].pTab = pExpr->y.pTab; + pSort->aDefer[nDefer].iCsr = pExpr->iTable; + pSort->aDefer[nDefer].nKey = nKey; + nDefer++; + } + } + pItem->fg.bSorterRef = 1; + } + } + } + pSort->nDefer = (u8)nDefer; + *ppExtra = pExtra; +} +#endif + +/* +** This routine generates the code for the inside of the inner loop +** of a SELECT. +** +** If srcTab is negative, then the p->pEList expressions +** are evaluated in order to get the data for this row. If srcTab is +** zero or more, then data is pulled from srcTab and p->pEList is used only +** to get the number of columns and the collation sequence for each column. +*/ +static void selectInnerLoop( + Parse *pParse, /* The parser context */ + Select *p, /* The complete select statement being coded */ + int srcTab, /* Pull data from this table if non-negative */ + SortCtx *pSort, /* If not NULL, info on how to process ORDER BY */ + DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */ + SelectDest *pDest, /* How to dispose of the results */ + int iContinue, /* Jump here to continue with next row */ + int iBreak /* Jump here to break out of the inner loop */ +){ + Vdbe *v = pParse->pVdbe; + int i; + int hasDistinct; /* True if the DISTINCT keyword is present */ + int eDest = pDest->eDest; /* How to dispose of results */ + int iParm = pDest->iSDParm; /* First argument to disposal method */ + int nResultCol; /* Number of result columns */ + int nPrefixReg = 0; /* Number of extra registers before regResult */ + RowLoadInfo sRowLoadInfo; /* Info for deferred row loading */ + + /* Usually, regResult is the first cell in an array of memory cells + ** containing the current result row. In this case regOrig is set to the + ** same value. However, if the results are being sent to the sorter, the + ** values for any expressions that are also part of the sort-key are omitted + ** from this array. In this case regOrig is set to zero. */ + int regResult; /* Start of memory holding current results */ + int regOrig; /* Start of memory holding full result (or 0) */ + + assert( v ); + assert( p->pEList!=0 ); + hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP; + if( pSort && pSort->pOrderBy==0 ) pSort = 0; + if( pSort==0 && !hasDistinct ){ + assert( iContinue!=0 ); + codeOffset(v, p->iOffset, iContinue); + } + + /* Pull the requested columns. + */ + nResultCol = p->pEList->nExpr; + + if( pDest->iSdst==0 ){ + if( pSort ){ + nPrefixReg = pSort->pOrderBy->nExpr; + if( !(pSort->sortFlags & SORTFLAG_UseSorter) ) nPrefixReg++; + pParse->nMem += nPrefixReg; + } + pDest->iSdst = pParse->nMem+1; + pParse->nMem += nResultCol; + }else if( pDest->iSdst+nResultCol > pParse->nMem ){ + /* This is an error condition that can result, for example, when a SELECT + ** on the right-hand side of an INSERT contains more result columns than + ** there are columns in the table on the left. The error will be caught + ** and reported later. But we need to make sure enough memory is allocated + ** to avoid other spurious errors in the meantime. */ + pParse->nMem += nResultCol; + } + pDest->nSdst = nResultCol; + regOrig = regResult = pDest->iSdst; + if( srcTab>=0 ){ + for(i=0; i<nResultCol; i++){ + sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i); + VdbeComment((v, "%s", p->pEList->a[i].zEName)); + } + }else if( eDest!=SRT_Exists ){ +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + ExprList *pExtra = 0; +#endif + /* If the destination is an EXISTS(...) expression, the actual + ** values returned by the SELECT are not required. + */ + u8 ecelFlags; /* "ecel" is an abbreviation of "ExprCodeExprList" */ + ExprList *pEList; + if( eDest==SRT_Mem || eDest==SRT_Output || eDest==SRT_Coroutine ){ + ecelFlags = SQLITE_ECEL_DUP; + }else{ + ecelFlags = 0; + } + if( pSort && hasDistinct==0 && eDest!=SRT_EphemTab && eDest!=SRT_Table ){ + /* For each expression in p->pEList that is a copy of an expression in + ** the ORDER BY clause (pSort->pOrderBy), set the associated + ** iOrderByCol value to one more than the index of the ORDER BY + ** expression within the sort-key that pushOntoSorter() will generate. + ** This allows the p->pEList field to be omitted from the sorted record, + ** saving space and CPU cycles. */ + ecelFlags |= (SQLITE_ECEL_OMITREF|SQLITE_ECEL_REF); + + for(i=pSort->nOBSat; i<pSort->pOrderBy->nExpr; i++){ + int j; + if( (j = pSort->pOrderBy->a[i].u.x.iOrderByCol)>0 ){ + p->pEList->a[j-1].u.x.iOrderByCol = i+1-pSort->nOBSat; + } + } +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + selectExprDefer(pParse, pSort, p->pEList, &pExtra); + if( pExtra && pParse->db->mallocFailed==0 ){ + /* If there are any extra PK columns to add to the sorter records, + ** allocate extra memory cells and adjust the OpenEphemeral + ** instruction to account for the larger records. This is only + ** required if there are one or more WITHOUT ROWID tables with + ** composite primary keys in the SortCtx.aDefer[] array. */ + VdbeOp *pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex); + pOp->p2 += (pExtra->nExpr - pSort->nDefer); + pOp->p4.pKeyInfo->nAllField += (pExtra->nExpr - pSort->nDefer); + pParse->nMem += pExtra->nExpr; + } +#endif + + /* Adjust nResultCol to account for columns that are omitted + ** from the sorter by the optimizations in this branch */ + pEList = p->pEList; + for(i=0; i<pEList->nExpr; i++){ + if( pEList->a[i].u.x.iOrderByCol>0 +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + || pEList->a[i].fg.bSorterRef +#endif + ){ + nResultCol--; + regOrig = 0; + } + } + + testcase( regOrig ); + testcase( eDest==SRT_Set ); + testcase( eDest==SRT_Mem ); + testcase( eDest==SRT_Coroutine ); + testcase( eDest==SRT_Output ); + assert( eDest==SRT_Set || eDest==SRT_Mem + || eDest==SRT_Coroutine || eDest==SRT_Output + || eDest==SRT_Upfrom ); + } + sRowLoadInfo.regResult = regResult; + sRowLoadInfo.ecelFlags = ecelFlags; +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + sRowLoadInfo.pExtra = pExtra; + sRowLoadInfo.regExtraResult = regResult + nResultCol; + if( pExtra ) nResultCol += pExtra->nExpr; +#endif + if( p->iLimit + && (ecelFlags & SQLITE_ECEL_OMITREF)!=0 + && nPrefixReg>0 + ){ + assert( pSort!=0 ); + assert( hasDistinct==0 ); + pSort->pDeferredRowLoad = &sRowLoadInfo; + regOrig = 0; + }else{ + innerLoopLoadRow(pParse, p, &sRowLoadInfo); + } + } + + /* If the DISTINCT keyword was present on the SELECT statement + ** and this row has been seen before, then do not make this row + ** part of the result. + */ + if( hasDistinct ){ + int eType = pDistinct->eTnctType; + int iTab = pDistinct->tabTnct; + assert( nResultCol==p->pEList->nExpr ); + iTab = codeDistinct(pParse, eType, iTab, iContinue, p->pEList, regResult); + fixDistinctOpenEph(pParse, eType, iTab, pDistinct->addrTnct); + if( pSort==0 ){ + codeOffset(v, p->iOffset, iContinue); + } + } + + switch( eDest ){ + /* In this mode, write each query result to the key of the temporary + ** table iParm. + */ +#ifndef SQLITE_OMIT_COMPOUND_SELECT + case SRT_Union: { + int r1; + r1 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol); + sqlite3ReleaseTempReg(pParse, r1); + break; + } + + /* Construct a record from the query result, but instead of + ** saving that record, use it as a key to delete elements from + ** the temporary table iParm. + */ + case SRT_Except: { + sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nResultCol); + break; + } +#endif /* SQLITE_OMIT_COMPOUND_SELECT */ + + /* Store the result as data using a unique key. + */ + case SRT_Fifo: + case SRT_DistFifo: + case SRT_Table: + case SRT_EphemTab: { + int r1 = sqlite3GetTempRange(pParse, nPrefixReg+1); + testcase( eDest==SRT_Table ); + testcase( eDest==SRT_EphemTab ); + testcase( eDest==SRT_Fifo ); + testcase( eDest==SRT_DistFifo ); + sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1+nPrefixReg); +#if !defined(SQLITE_ENABLE_NULL_TRIM) && defined(SQLITE_DEBUG) + /* A destination of SRT_Table and a non-zero iSDParm2 parameter means + ** that this is an "UPDATE ... FROM" on a virtual table or view. In this + ** case set the p5 parameter of the OP_MakeRecord to OPFLAG_NOCHNG_MAGIC. + ** This does not affect operation in any way - it just allows MakeRecord + ** to process OPFLAG_NOCHANGE values without an assert() failing. */ + if( eDest==SRT_Table && pDest->iSDParm2 ){ + sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG_MAGIC); + } +#endif +#ifndef SQLITE_OMIT_CTE + if( eDest==SRT_DistFifo ){ + /* If the destination is DistFifo, then cursor (iParm+1) is open + ** on an ephemeral index. If the current row is already present + ** in the index, do not write it to the output. If not, add the + ** current row to the index and proceed with writing it to the + ** output table as well. */ + int addr = sqlite3VdbeCurrentAddr(v) + 4; + sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0); + VdbeCoverage(v); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm+1, r1,regResult,nResultCol); + assert( pSort==0 ); + } +#endif + if( pSort ){ + assert( regResult==regOrig ); + pushOntoSorter(pParse, pSort, p, r1+nPrefixReg, regOrig, 1, nPrefixReg); + }else{ + int r2 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2); + sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2); + sqlite3VdbeChangeP5(v, OPFLAG_APPEND); + sqlite3ReleaseTempReg(pParse, r2); + } + sqlite3ReleaseTempRange(pParse, r1, nPrefixReg+1); + break; + } + + case SRT_Upfrom: { + if( pSort ){ + pushOntoSorter( + pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); + }else{ + int i2 = pDest->iSDParm2; + int r1 = sqlite3GetTempReg(pParse); + + /* If the UPDATE FROM join is an aggregate that matches no rows, it + ** might still be trying to return one row, because that is what + ** aggregates do. Don't record that empty row in the output table. */ + sqlite3VdbeAddOp2(v, OP_IsNull, regResult, iBreak); VdbeCoverage(v); + + sqlite3VdbeAddOp3(v, OP_MakeRecord, + regResult+(i2<0), nResultCol-(i2<0), r1); + if( i2<0 ){ + sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regResult); + }else{ + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, i2); + } + } + break; + } + +#ifndef SQLITE_OMIT_SUBQUERY + /* If we are creating a set for an "expr IN (SELECT ...)" construct, + ** then there should be a single item on the stack. Write this + ** item into the set table with bogus data. + */ + case SRT_Set: { + if( pSort ){ + /* At first glance you would think we could optimize out the + ** ORDER BY in this case since the order of entries in the set + ** does not matter. But there might be a LIMIT clause, in which + ** case the order does matter */ + pushOntoSorter( + pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); + }else{ + int r1 = sqlite3GetTempReg(pParse); + assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol ); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol, + r1, pDest->zAffSdst, nResultCol); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol); + sqlite3ReleaseTempReg(pParse, r1); + } + break; + } + + + /* If any row exist in the result set, record that fact and abort. + */ + case SRT_Exists: { + sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm); + /* The LIMIT clause will terminate the loop for us */ + break; + } + + /* If this is a scalar select that is part of an expression, then + ** store the results in the appropriate memory cell or array of + ** memory cells and break out of the scan loop. + */ + case SRT_Mem: { + if( pSort ){ + assert( nResultCol<=pDest->nSdst ); + pushOntoSorter( + pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); + }else{ + assert( nResultCol==pDest->nSdst ); + assert( regResult==iParm ); + /* The LIMIT clause will jump out of the loop for us */ + } + break; + } +#endif /* #ifndef SQLITE_OMIT_SUBQUERY */ + + case SRT_Coroutine: /* Send data to a co-routine */ + case SRT_Output: { /* Return the results */ + testcase( eDest==SRT_Coroutine ); + testcase( eDest==SRT_Output ); + if( pSort ){ + pushOntoSorter(pParse, pSort, p, regResult, regOrig, nResultCol, + nPrefixReg); + }else if( eDest==SRT_Coroutine ){ + sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm); + }else{ + sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol); + } + break; + } + +#ifndef SQLITE_OMIT_CTE + /* Write the results into a priority queue that is order according to + ** pDest->pOrderBy (in pSO). pDest->iSDParm (in iParm) is the cursor for an + ** index with pSO->nExpr+2 columns. Build a key using pSO for the first + ** pSO->nExpr columns, then make sure all keys are unique by adding a + ** final OP_Sequence column. The last column is the record as a blob. + */ + case SRT_DistQueue: + case SRT_Queue: { + int nKey; + int r1, r2, r3; + int addrTest = 0; + ExprList *pSO; + pSO = pDest->pOrderBy; + assert( pSO ); + nKey = pSO->nExpr; + r1 = sqlite3GetTempReg(pParse); + r2 = sqlite3GetTempRange(pParse, nKey+2); + r3 = r2+nKey+1; + if( eDest==SRT_DistQueue ){ + /* If the destination is DistQueue, then cursor (iParm+1) is open + ** on a second ephemeral index that holds all values every previously + ** added to the queue. */ + addrTest = sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, 0, + regResult, nResultCol); + VdbeCoverage(v); + } + sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r3); + if( eDest==SRT_DistQueue ){ + sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r3); + sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT); + } + for(i=0; i<nKey; i++){ + sqlite3VdbeAddOp2(v, OP_SCopy, + regResult + pSO->a[i].u.x.iOrderByCol - 1, + r2+i); + } + sqlite3VdbeAddOp2(v, OP_Sequence, iParm, r2+nKey); + sqlite3VdbeAddOp3(v, OP_MakeRecord, r2, nKey+2, r1); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, r2, nKey+2); + if( addrTest ) sqlite3VdbeJumpHere(v, addrTest); + sqlite3ReleaseTempReg(pParse, r1); + sqlite3ReleaseTempRange(pParse, r2, nKey+2); + break; + } +#endif /* SQLITE_OMIT_CTE */ + + + +#if !defined(SQLITE_OMIT_TRIGGER) + /* Discard the results. This is used for SELECT statements inside + ** the body of a TRIGGER. The purpose of such selects is to call + ** user-defined functions that have side effects. We do not care + ** about the actual results of the select. + */ + default: { + assert( eDest==SRT_Discard ); + break; + } +#endif + } + + /* Jump to the end of the loop if the LIMIT is reached. Except, if + ** there is a sorter, in which case the sorter has already limited + ** the output for us. + */ + if( pSort==0 && p->iLimit ){ + sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v); + } +} + +/* +** Allocate a KeyInfo object sufficient for an index of N key columns and +** X extra columns. +*/ +KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N, int X){ + int nExtra = (N+X)*(sizeof(CollSeq*)+1) - sizeof(CollSeq*); + KeyInfo *p = sqlite3DbMallocRawNN(db, sizeof(KeyInfo) + nExtra); + if( p ){ + p->aSortFlags = (u8*)&p->aColl[N+X]; + p->nKeyField = (u16)N; + p->nAllField = (u16)(N+X); + p->enc = ENC(db); + p->db = db; + p->nRef = 1; + memset(&p[1], 0, nExtra); + }else{ + return (KeyInfo*)sqlite3OomFault(db); + } + return p; +} + +/* +** Deallocate a KeyInfo object +*/ +void sqlite3KeyInfoUnref(KeyInfo *p){ + if( p ){ + assert( p->db!=0 ); + assert( p->nRef>0 ); + p->nRef--; + if( p->nRef==0 ) sqlite3DbNNFreeNN(p->db, p); + } +} + +/* +** Make a new pointer to a KeyInfo object +*/ +KeyInfo *sqlite3KeyInfoRef(KeyInfo *p){ + if( p ){ + assert( p->nRef>0 ); + p->nRef++; + } + return p; +} + +#ifdef SQLITE_DEBUG +/* +** Return TRUE if a KeyInfo object can be change. The KeyInfo object +** can only be changed if this is just a single reference to the object. +** +** This routine is used only inside of assert() statements. +*/ +int sqlite3KeyInfoIsWriteable(KeyInfo *p){ return p->nRef==1; } +#endif /* SQLITE_DEBUG */ + +/* +** Given an expression list, generate a KeyInfo structure that records +** the collating sequence for each expression in that expression list. +** +** If the ExprList is an ORDER BY or GROUP BY clause then the resulting +** KeyInfo structure is appropriate for initializing a virtual index to +** implement that clause. If the ExprList is the result set of a SELECT +** then the KeyInfo structure is appropriate for initializing a virtual +** index to implement a DISTINCT test. +** +** Space to hold the KeyInfo structure is obtained from malloc. The calling +** function is responsible for seeing that this structure is eventually +** freed. +*/ +KeyInfo *sqlite3KeyInfoFromExprList( + Parse *pParse, /* Parsing context */ + ExprList *pList, /* Form the KeyInfo object from this ExprList */ + int iStart, /* Begin with this column of pList */ + int nExtra /* Add this many extra columns to the end */ +){ + int nExpr; + KeyInfo *pInfo; + struct ExprList_item *pItem; + sqlite3 *db = pParse->db; + int i; + + nExpr = pList->nExpr; + pInfo = sqlite3KeyInfoAlloc(db, nExpr-iStart, nExtra+1); + if( pInfo ){ + assert( sqlite3KeyInfoIsWriteable(pInfo) ); + for(i=iStart, pItem=pList->a+iStart; i<nExpr; i++, pItem++){ + pInfo->aColl[i-iStart] = sqlite3ExprNNCollSeq(pParse, pItem->pExpr); + pInfo->aSortFlags[i-iStart] = pItem->fg.sortFlags; + } + } + return pInfo; +} + +/* +** Name of the connection operator, used for error messages. +*/ +const char *sqlite3SelectOpName(int id){ + char *z; + switch( id ){ + case TK_ALL: z = "UNION ALL"; break; + case TK_INTERSECT: z = "INTERSECT"; break; + case TK_EXCEPT: z = "EXCEPT"; break; + default: z = "UNION"; break; + } + return z; +} + +#ifndef SQLITE_OMIT_EXPLAIN +/* +** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function +** is a no-op. Otherwise, it adds a single row of output to the EQP result, +** where the caption is of the form: +** +** "USE TEMP B-TREE FOR xxx" +** +** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which +** is determined by the zUsage argument. +*/ +static void explainTempTable(Parse *pParse, const char *zUsage){ + ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s", zUsage)); +} + +/* +** Assign expression b to lvalue a. A second, no-op, version of this macro +** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code +** in sqlite3Select() to assign values to structure member variables that +** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the +** code with #ifndef directives. +*/ +# define explainSetInteger(a, b) a = b + +#else +/* No-op versions of the explainXXX() functions and macros. */ +# define explainTempTable(y,z) +# define explainSetInteger(y,z) +#endif + + +/* +** If the inner loop was generated using a non-null pOrderBy argument, +** then the results were placed in a sorter. After the loop is terminated +** we need to run the sorter and output the results. The following +** routine generates the code needed to do that. +*/ +static void generateSortTail( + Parse *pParse, /* Parsing context */ + Select *p, /* The SELECT statement */ + SortCtx *pSort, /* Information on the ORDER BY clause */ + int nColumn, /* Number of columns of data */ + SelectDest *pDest /* Write the sorted results here */ +){ + Vdbe *v = pParse->pVdbe; /* The prepared statement */ + int addrBreak = pSort->labelDone; /* Jump here to exit loop */ + int addrContinue = sqlite3VdbeMakeLabel(pParse);/* Jump here for next cycle */ + int addr; /* Top of output loop. Jump for Next. */ + int addrOnce = 0; + int iTab; + ExprList *pOrderBy = pSort->pOrderBy; + int eDest = pDest->eDest; + int iParm = pDest->iSDParm; + int regRow; + int regRowid; + int iCol; + int nKey; /* Number of key columns in sorter record */ + int iSortTab; /* Sorter cursor to read from */ + int i; + int bSeq; /* True if sorter record includes seq. no. */ + int nRefKey = 0; + struct ExprList_item *aOutEx = p->pEList->a; +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + int addrExplain; /* Address of OP_Explain instruction */ +#endif + + ExplainQueryPlan2(addrExplain, (pParse, 0, + "USE TEMP B-TREE FOR %sORDER BY", pSort->nOBSat>0?"RIGHT PART OF ":"") + ); + sqlite3VdbeScanStatusRange(v, addrExplain,pSort->addrPush,pSort->addrPushEnd); + sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, pSort->addrPush); + + + assert( addrBreak<0 ); + if( pSort->labelBkOut ){ + sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut); + sqlite3VdbeGoto(v, addrBreak); + sqlite3VdbeResolveLabel(v, pSort->labelBkOut); + } + +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + /* Open any cursors needed for sorter-reference expressions */ + for(i=0; i<pSort->nDefer; i++){ + Table *pTab = pSort->aDefer[i].pTab; + int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema); + sqlite3OpenTable(pParse, pSort->aDefer[i].iCsr, iDb, pTab, OP_OpenRead); + nRefKey = MAX(nRefKey, pSort->aDefer[i].nKey); + } +#endif + + iTab = pSort->iECursor; + if( eDest==SRT_Output || eDest==SRT_Coroutine || eDest==SRT_Mem ){ + if( eDest==SRT_Mem && p->iOffset ){ + sqlite3VdbeAddOp2(v, OP_Null, 0, pDest->iSdst); + } + regRowid = 0; + regRow = pDest->iSdst; + }else{ + regRowid = sqlite3GetTempReg(pParse); + if( eDest==SRT_EphemTab || eDest==SRT_Table ){ + regRow = sqlite3GetTempReg(pParse); + nColumn = 0; + }else{ + regRow = sqlite3GetTempRange(pParse, nColumn); + } + } + nKey = pOrderBy->nExpr - pSort->nOBSat; + if( pSort->sortFlags & SORTFLAG_UseSorter ){ + int regSortOut = ++pParse->nMem; + iSortTab = pParse->nTab++; + if( pSort->labelBkOut ){ + addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v); + } + sqlite3VdbeAddOp3(v, OP_OpenPseudo, iSortTab, regSortOut, + nKey+1+nColumn+nRefKey); + if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce); + addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak); + VdbeCoverage(v); + assert( p->iLimit==0 && p->iOffset==0 ); + sqlite3VdbeAddOp3(v, OP_SorterData, iTab, regSortOut, iSortTab); + bSeq = 0; + }else{ + addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak); VdbeCoverage(v); + codeOffset(v, p->iOffset, addrContinue); + iSortTab = iTab; + bSeq = 1; + if( p->iOffset>0 ){ + sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1); + } + } + for(i=0, iCol=nKey+bSeq-1; i<nColumn; i++){ +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + if( aOutEx[i].fg.bSorterRef ) continue; +#endif + if( aOutEx[i].u.x.iOrderByCol==0 ) iCol++; + } +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + if( pSort->nDefer ){ + int iKey = iCol+1; + int regKey = sqlite3GetTempRange(pParse, nRefKey); + + for(i=0; i<pSort->nDefer; i++){ + int iCsr = pSort->aDefer[i].iCsr; + Table *pTab = pSort->aDefer[i].pTab; + int nKey = pSort->aDefer[i].nKey; + + sqlite3VdbeAddOp1(v, OP_NullRow, iCsr); + if( HasRowid(pTab) ){ + sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iKey++, regKey); + sqlite3VdbeAddOp3(v, OP_SeekRowid, iCsr, + sqlite3VdbeCurrentAddr(v)+1, regKey); + }else{ + int k; + int iJmp; + assert( sqlite3PrimaryKeyIndex(pTab)->nKeyCol==nKey ); + for(k=0; k<nKey; k++){ + sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iKey++, regKey+k); + } + iJmp = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp4Int(v, OP_SeekGE, iCsr, iJmp+2, regKey, nKey); + sqlite3VdbeAddOp4Int(v, OP_IdxLE, iCsr, iJmp+3, regKey, nKey); + sqlite3VdbeAddOp1(v, OP_NullRow, iCsr); + } + } + sqlite3ReleaseTempRange(pParse, regKey, nRefKey); + } +#endif + for(i=nColumn-1; i>=0; i--){ +#ifdef SQLITE_ENABLE_SORTER_REFERENCES + if( aOutEx[i].fg.bSorterRef ){ + sqlite3ExprCode(pParse, aOutEx[i].pExpr, regRow+i); + }else +#endif + { + int iRead; + if( aOutEx[i].u.x.iOrderByCol ){ + iRead = aOutEx[i].u.x.iOrderByCol-1; + }else{ + iRead = iCol--; + } + sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iRead, regRow+i); + VdbeComment((v, "%s", aOutEx[i].zEName)); + } + } + sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1); + switch( eDest ){ + case SRT_Table: + case SRT_EphemTab: { + sqlite3VdbeAddOp3(v, OP_Column, iSortTab, nKey+bSeq, regRow); + sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid); + sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid); + sqlite3VdbeChangeP5(v, OPFLAG_APPEND); + break; + } +#ifndef SQLITE_OMIT_SUBQUERY + case SRT_Set: { + assert( nColumn==sqlite3Strlen30(pDest->zAffSdst) ); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, nColumn, regRowid, + pDest->zAffSdst, nColumn); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, regRowid, regRow, nColumn); + break; + } + case SRT_Mem: { + /* The LIMIT clause will terminate the loop for us */ + break; + } +#endif + case SRT_Upfrom: { + int i2 = pDest->iSDParm2; + int r1 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp3(v, OP_MakeRecord,regRow+(i2<0),nColumn-(i2<0),r1); + if( i2<0 ){ + sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regRow); + }else{ + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regRow, i2); + } + break; + } + default: { + assert( eDest==SRT_Output || eDest==SRT_Coroutine ); + testcase( eDest==SRT_Output ); + testcase( eDest==SRT_Coroutine ); + if( eDest==SRT_Output ){ + sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iSdst, nColumn); + }else{ + sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm); + } + break; + } + } + if( regRowid ){ + if( eDest==SRT_Set ){ + sqlite3ReleaseTempRange(pParse, regRow, nColumn); + }else{ + sqlite3ReleaseTempReg(pParse, regRow); + } + sqlite3ReleaseTempReg(pParse, regRowid); + } + /* The bottom of the loop + */ + sqlite3VdbeResolveLabel(v, addrContinue); + if( pSort->sortFlags & SORTFLAG_UseSorter ){ + sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr); VdbeCoverage(v); + }else{ + sqlite3VdbeAddOp2(v, OP_Next, iTab, addr); VdbeCoverage(v); + } + sqlite3VdbeScanStatusRange(v, addrExplain, sqlite3VdbeCurrentAddr(v)-1, -1); + if( pSort->regReturn ) sqlite3VdbeAddOp1(v, OP_Return, pSort->regReturn); + sqlite3VdbeResolveLabel(v, addrBreak); +} + +/* +** Return a pointer to a string containing the 'declaration type' of the +** expression pExpr. The string may be treated as static by the caller. +** +** The declaration type is the exact datatype definition extracted from the +** original CREATE TABLE statement if the expression is a column. The +** declaration type for a ROWID field is INTEGER. Exactly when an expression +** is considered a column can be complex in the presence of subqueries. The +** result-set expression in all of the following SELECT statements is +** considered a column by this function. +** +** SELECT col FROM tbl; +** SELECT (SELECT col FROM tbl; +** SELECT (SELECT col FROM tbl); +** SELECT abc FROM (SELECT col AS abc FROM tbl); +** +** The declaration type for any expression other than a column is NULL. +** +** This routine has either 3 or 6 parameters depending on whether or not +** the SQLITE_ENABLE_COLUMN_METADATA compile-time option is used. +*/ +#ifdef SQLITE_ENABLE_COLUMN_METADATA +# define columnType(A,B,C,D,E) columnTypeImpl(A,B,C,D,E) +#else /* if !defined(SQLITE_ENABLE_COLUMN_METADATA) */ +# define columnType(A,B,C,D,E) columnTypeImpl(A,B) +#endif +static const char *columnTypeImpl( + NameContext *pNC, +#ifndef SQLITE_ENABLE_COLUMN_METADATA + Expr *pExpr +#else + Expr *pExpr, + const char **pzOrigDb, + const char **pzOrigTab, + const char **pzOrigCol +#endif +){ + char const *zType = 0; + int j; +#ifdef SQLITE_ENABLE_COLUMN_METADATA + char const *zOrigDb = 0; + char const *zOrigTab = 0; + char const *zOrigCol = 0; +#endif + + assert( pExpr!=0 ); + assert( pNC->pSrcList!=0 ); + switch( pExpr->op ){ + case TK_COLUMN: { + /* The expression is a column. Locate the table the column is being + ** extracted from in NameContext.pSrcList. This table may be real + ** database table or a subquery. + */ + Table *pTab = 0; /* Table structure column is extracted from */ + Select *pS = 0; /* Select the column is extracted from */ + int iCol = pExpr->iColumn; /* Index of column in pTab */ + while( pNC && !pTab ){ + SrcList *pTabList = pNC->pSrcList; + for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++); + if( j<pTabList->nSrc ){ + pTab = pTabList->a[j].pTab; + pS = pTabList->a[j].pSelect; + }else{ + pNC = pNC->pNext; + } + } + + if( pTab==0 ){ + /* At one time, code such as "SELECT new.x" within a trigger would + ** cause this condition to run. Since then, we have restructured how + ** trigger code is generated and so this condition is no longer + ** possible. However, it can still be true for statements like + ** the following: + ** + ** CREATE TABLE t1(col INTEGER); + ** SELECT (SELECT t1.col) FROM FROM t1; + ** + ** when columnType() is called on the expression "t1.col" in the + ** sub-select. In this case, set the column type to NULL, even + ** though it should really be "INTEGER". + ** + ** This is not a problem, as the column type of "t1.col" is never + ** used. When columnType() is called on the expression + ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT + ** branch below. */ + break; + } + + assert( pTab && ExprUseYTab(pExpr) && pExpr->y.pTab==pTab ); + if( pS ){ + /* The "table" is actually a sub-select or a view in the FROM clause + ** of the SELECT statement. Return the declaration type and origin + ** data for the result-set column of the sub-select. + */ + if( iCol<pS->pEList->nExpr +#ifdef SQLITE_ALLOW_ROWID_IN_VIEW + && iCol>=0 +#else + && ALWAYS(iCol>=0) +#endif + ){ + /* If iCol is less than zero, then the expression requests the + ** rowid of the sub-select or view. This expression is legal (see + ** test case misc2.2.2) - it always evaluates to NULL. + */ + NameContext sNC; + Expr *p = pS->pEList->a[iCol].pExpr; + sNC.pSrcList = pS->pSrc; + sNC.pNext = pNC; + sNC.pParse = pNC->pParse; + zType = columnType(&sNC, p,&zOrigDb,&zOrigTab,&zOrigCol); + } + }else{ + /* A real table or a CTE table */ + assert( !pS ); +#ifdef SQLITE_ENABLE_COLUMN_METADATA + if( iCol<0 ) iCol = pTab->iPKey; + assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) ); + if( iCol<0 ){ + zType = "INTEGER"; + zOrigCol = "rowid"; + }else{ + zOrigCol = pTab->aCol[iCol].zCnName; + zType = sqlite3ColumnType(&pTab->aCol[iCol],0); + } + zOrigTab = pTab->zName; + if( pNC->pParse && pTab->pSchema ){ + int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema); + zOrigDb = pNC->pParse->db->aDb[iDb].zDbSName; + } +#else + assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) ); + if( iCol<0 ){ + zType = "INTEGER"; + }else{ + zType = sqlite3ColumnType(&pTab->aCol[iCol],0); + } +#endif + } + break; + } +#ifndef SQLITE_OMIT_SUBQUERY + case TK_SELECT: { + /* The expression is a sub-select. Return the declaration type and + ** origin info for the single column in the result set of the SELECT + ** statement. + */ + NameContext sNC; + Select *pS; + Expr *p; + assert( ExprUseXSelect(pExpr) ); + pS = pExpr->x.pSelect; + p = pS->pEList->a[0].pExpr; + sNC.pSrcList = pS->pSrc; + sNC.pNext = pNC; + sNC.pParse = pNC->pParse; + zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol); + break; + } +#endif + } + +#ifdef SQLITE_ENABLE_COLUMN_METADATA + if( pzOrigDb ){ + assert( pzOrigTab && pzOrigCol ); + *pzOrigDb = zOrigDb; + *pzOrigTab = zOrigTab; + *pzOrigCol = zOrigCol; + } +#endif + return zType; +} + +/* +** Generate code that will tell the VDBE the declaration types of columns +** in the result set. +*/ +static void generateColumnTypes( + Parse *pParse, /* Parser context */ + SrcList *pTabList, /* List of tables */ + ExprList *pEList /* Expressions defining the result set */ +){ +#ifndef SQLITE_OMIT_DECLTYPE + Vdbe *v = pParse->pVdbe; + int i; + NameContext sNC; + sNC.pSrcList = pTabList; + sNC.pParse = pParse; + sNC.pNext = 0; + for(i=0; i<pEList->nExpr; i++){ + Expr *p = pEList->a[i].pExpr; + const char *zType; +#ifdef SQLITE_ENABLE_COLUMN_METADATA + const char *zOrigDb = 0; + const char *zOrigTab = 0; + const char *zOrigCol = 0; + zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol); + + /* The vdbe must make its own copy of the column-type and other + ** column specific strings, in case the schema is reset before this + ** virtual machine is deleted. + */ + sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, SQLITE_TRANSIENT); + sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, SQLITE_TRANSIENT); + sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, SQLITE_TRANSIENT); +#else + zType = columnType(&sNC, p, 0, 0, 0); +#endif + sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT); + } +#endif /* !defined(SQLITE_OMIT_DECLTYPE) */ +} + + +/* +** Compute the column names for a SELECT statement. +** +** The only guarantee that SQLite makes about column names is that if the +** column has an AS clause assigning it a name, that will be the name used. +** That is the only documented guarantee. However, countless applications +** developed over the years have made baseless assumptions about column names +** and will break if those assumptions changes. Hence, use extreme caution +** when modifying this routine to avoid breaking legacy. +** +** See Also: sqlite3ColumnsFromExprList() +** +** The PRAGMA short_column_names and PRAGMA full_column_names settings are +** deprecated. The default setting is short=ON, full=OFF. 99.9% of all +** applications should operate this way. Nevertheless, we need to support the +** other modes for legacy: +** +** short=OFF, full=OFF: Column name is the text of the expression has it +** originally appears in the SELECT statement. In +** other words, the zSpan of the result expression. +** +** short=ON, full=OFF: (This is the default setting). If the result +** refers directly to a table column, then the +** result column name is just the table column +** name: COLUMN. Otherwise use zSpan. +** +** full=ON, short=ANY: If the result refers directly to a table column, +** then the result column name with the table name +** prefix, ex: TABLE.COLUMN. Otherwise use zSpan. +*/ +void sqlite3GenerateColumnNames( + Parse *pParse, /* Parser context */ + Select *pSelect /* Generate column names for this SELECT statement */ +){ + Vdbe *v = pParse->pVdbe; + int i; + Table *pTab; + SrcList *pTabList; + ExprList *pEList; + sqlite3 *db = pParse->db; + int fullName; /* TABLE.COLUMN if no AS clause and is a direct table ref */ + int srcName; /* COLUMN or TABLE.COLUMN if no AS clause and is direct */ + + if( pParse->colNamesSet ) return; + /* Column names are determined by the left-most term of a compound select */ + while( pSelect->pPrior ) pSelect = pSelect->pPrior; + TREETRACE(0x80,pParse,pSelect,("generating column names\n")); + pTabList = pSelect->pSrc; + pEList = pSelect->pEList; + assert( v!=0 ); + assert( pTabList!=0 ); + pParse->colNamesSet = 1; + fullName = (db->flags & SQLITE_FullColNames)!=0; + srcName = (db->flags & SQLITE_ShortColNames)!=0 || fullName; + sqlite3VdbeSetNumCols(v, pEList->nExpr); + for(i=0; i<pEList->nExpr; i++){ + Expr *p = pEList->a[i].pExpr; + + assert( p!=0 ); + assert( p->op!=TK_AGG_COLUMN ); /* Agg processing has not run yet */ + assert( p->op!=TK_COLUMN + || (ExprUseYTab(p) && p->y.pTab!=0) ); /* Covering idx not yet coded */ + if( pEList->a[i].zEName && pEList->a[i].fg.eEName==ENAME_NAME ){ + /* An AS clause always takes first priority */ + char *zName = pEList->a[i].zEName; + sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT); + }else if( srcName && p->op==TK_COLUMN ){ + char *zCol; + int iCol = p->iColumn; + pTab = p->y.pTab; + assert( pTab!=0 ); + if( iCol<0 ) iCol = pTab->iPKey; + assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) ); + if( iCol<0 ){ + zCol = "rowid"; + }else{ + zCol = pTab->aCol[iCol].zCnName; + } + if( fullName ){ + char *zName = 0; + zName = sqlite3MPrintf(db, "%s.%s", pTab->zName, zCol); + sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_DYNAMIC); + }else{ + sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, SQLITE_TRANSIENT); + } + }else{ + const char *z = pEList->a[i].zEName; + z = z==0 ? sqlite3MPrintf(db, "column%d", i+1) : sqlite3DbStrDup(db, z); + sqlite3VdbeSetColName(v, i, COLNAME_NAME, z, SQLITE_DYNAMIC); + } + } + generateColumnTypes(pParse, pTabList, pEList); +} + +/* +** Given an expression list (which is really the list of expressions +** that form the result set of a SELECT statement) compute appropriate +** column names for a table that would hold the expression list. +** +** All column names will be unique. +** +** Only the column names are computed. Column.zType, Column.zColl, +** and other fields of Column are zeroed. +** +** Return SQLITE_OK on success. If a memory allocation error occurs, +** store NULL in *paCol and 0 in *pnCol and return SQLITE_NOMEM. +** +** The only guarantee that SQLite makes about column names is that if the +** column has an AS clause assigning it a name, that will be the name used. +** That is the only documented guarantee. However, countless applications +** developed over the years have made baseless assumptions about column names +** and will break if those assumptions changes. Hence, use extreme caution +** when modifying this routine to avoid breaking legacy. +** +** See Also: sqlite3GenerateColumnNames() +*/ +int sqlite3ColumnsFromExprList( + Parse *pParse, /* Parsing context */ + ExprList *pEList, /* Expr list from which to derive column names */ + i16 *pnCol, /* Write the number of columns here */ + Column **paCol /* Write the new column list here */ +){ + sqlite3 *db = pParse->db; /* Database connection */ + int i, j; /* Loop counters */ + u32 cnt; /* Index added to make the name unique */ + Column *aCol, *pCol; /* For looping over result columns */ + int nCol; /* Number of columns in the result set */ + char *zName; /* Column name */ + int nName; /* Size of name in zName[] */ + Hash ht; /* Hash table of column names */ + Table *pTab; + + sqlite3HashInit(&ht); + if( pEList ){ + nCol = pEList->nExpr; + aCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol); + testcase( aCol==0 ); + if( NEVER(nCol>32767) ) nCol = 32767; + }else{ + nCol = 0; + aCol = 0; + } + assert( nCol==(i16)nCol ); + *pnCol = nCol; + *paCol = aCol; + + for(i=0, pCol=aCol; i<nCol && !pParse->nErr; i++, pCol++){ + struct ExprList_item *pX = &pEList->a[i]; + struct ExprList_item *pCollide; + /* Get an appropriate name for the column + */ + if( (zName = pX->zEName)!=0 && pX->fg.eEName==ENAME_NAME ){ + /* If the column contains an "AS <name>" phrase, use <name> as the name */ + }else{ + Expr *pColExpr = sqlite3ExprSkipCollateAndLikely(pX->pExpr); + while( ALWAYS(pColExpr!=0) && pColExpr->op==TK_DOT ){ + pColExpr = pColExpr->pRight; + assert( pColExpr!=0 ); + } + if( pColExpr->op==TK_COLUMN + && ALWAYS( ExprUseYTab(pColExpr) ) + && ALWAYS( pColExpr->y.pTab!=0 ) + ){ + /* For columns use the column name name */ + int iCol = pColExpr->iColumn; + pTab = pColExpr->y.pTab; + if( iCol<0 ) iCol = pTab->iPKey; + zName = iCol>=0 ? pTab->aCol[iCol].zCnName : "rowid"; + }else if( pColExpr->op==TK_ID ){ + assert( !ExprHasProperty(pColExpr, EP_IntValue) ); + zName = pColExpr->u.zToken; + }else{ + /* Use the original text of the column expression as its name */ + assert( zName==pX->zEName ); /* pointer comparison intended */ + } + } + if( zName && !sqlite3IsTrueOrFalse(zName) ){ + zName = sqlite3DbStrDup(db, zName); + }else{ + zName = sqlite3MPrintf(db,"column%d",i+1); + } + + /* Make sure the column name is unique. If the name is not unique, + ** append an integer to the name so that it becomes unique. + */ + cnt = 0; + while( zName && (pCollide = sqlite3HashFind(&ht, zName))!=0 ){ + if( pCollide->fg.bUsingTerm ){ + pCol->colFlags |= COLFLAG_NOEXPAND; + } + nName = sqlite3Strlen30(zName); + if( nName>0 ){ + for(j=nName-1; j>0 && sqlite3Isdigit(zName[j]); j--){} + if( zName[j]==':' ) nName = j; + } + zName = sqlite3MPrintf(db, "%.*z:%u", nName, zName, ++cnt); + sqlite3ProgressCheck(pParse); + if( cnt>3 ){ + sqlite3_randomness(sizeof(cnt), &cnt); + } + } + pCol->zCnName = zName; + pCol->hName = sqlite3StrIHash(zName); + if( pX->fg.bNoExpand ){ + pCol->colFlags |= COLFLAG_NOEXPAND; + } + sqlite3ColumnPropertiesFromName(0, pCol); + if( zName && sqlite3HashInsert(&ht, zName, pX)==pX ){ + sqlite3OomFault(db); + } + } + sqlite3HashClear(&ht); + if( pParse->nErr ){ + for(j=0; j<i; j++){ + sqlite3DbFree(db, aCol[j].zCnName); + } + sqlite3DbFree(db, aCol); + *paCol = 0; + *pnCol = 0; + return pParse->rc; + } + return SQLITE_OK; +} + +/* +** pTab is a transient Table object that represents a subquery of some +** kind (maybe a parenthesized subquery in the FROM clause of a larger +** query, or a VIEW, or a CTE). This routine computes type information +** for that Table object based on the Select object that implements the +** subquery. For the purposes of this routine, "type information" means: +** +** * The datatype name, as it might appear in a CREATE TABLE statement +** * Which collating sequence to use for the column +** * The affinity of the column +*/ +void sqlite3SubqueryColumnTypes( + Parse *pParse, /* Parsing contexts */ + Table *pTab, /* Add column type information to this table */ + Select *pSelect, /* SELECT used to determine types and collations */ + char aff /* Default affinity. */ +){ + sqlite3 *db = pParse->db; + Column *pCol; + CollSeq *pColl; + int i,j; + Expr *p; + struct ExprList_item *a; + NameContext sNC; + + assert( pSelect!=0 ); + testcase( (pSelect->selFlags & SF_Resolved)==0 ); + assert( (pSelect->selFlags & SF_Resolved)!=0 || IN_RENAME_OBJECT ); + assert( pTab->nCol==pSelect->pEList->nExpr || pParse->nErr>0 ); + assert( aff==SQLITE_AFF_NONE || aff==SQLITE_AFF_BLOB ); + if( db->mallocFailed || IN_RENAME_OBJECT ) return; + while( pSelect->pPrior ) pSelect = pSelect->pPrior; + a = pSelect->pEList->a; + memset(&sNC, 0, sizeof(sNC)); + sNC.pSrcList = pSelect->pSrc; + for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){ + const char *zType; + i64 n; + pTab->tabFlags |= (pCol->colFlags & COLFLAG_NOINSERT); + p = a[i].pExpr; + /* pCol->szEst = ... // Column size est for SELECT tables never used */ + pCol->affinity = sqlite3ExprAffinity(p); + if( pCol->affinity<=SQLITE_AFF_NONE ){ + pCol->affinity = aff; + } + if( pCol->affinity>=SQLITE_AFF_TEXT && pSelect->pNext ){ + int m = 0; + Select *pS2; + for(m=0, pS2=pSelect->pNext; pS2; pS2=pS2->pNext){ + m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr); + } + if( pCol->affinity==SQLITE_AFF_TEXT && (m&0x01)!=0 ){ + pCol->affinity = SQLITE_AFF_BLOB; + }else + if( pCol->affinity>=SQLITE_AFF_NUMERIC && (m&0x02)!=0 ){ + pCol->affinity = SQLITE_AFF_BLOB; + } + if( pCol->affinity>=SQLITE_AFF_NUMERIC && p->op==TK_CAST ){ + pCol->affinity = SQLITE_AFF_FLEXNUM; + } + } + zType = columnType(&sNC, p, 0, 0, 0); + if( zType==0 || pCol->affinity!=sqlite3AffinityType(zType, 0) ){ + if( pCol->affinity==SQLITE_AFF_NUMERIC + || pCol->affinity==SQLITE_AFF_FLEXNUM + ){ + zType = "NUM"; + }else{ + zType = 0; + for(j=1; j<SQLITE_N_STDTYPE; j++){ + if( sqlite3StdTypeAffinity[j]==pCol->affinity ){ + zType = sqlite3StdType[j]; + break; + } + } + } + } + if( zType ){ + i64 m = sqlite3Strlen30(zType); + n = sqlite3Strlen30(pCol->zCnName); + pCol->zCnName = sqlite3DbReallocOrFree(db, pCol->zCnName, n+m+2); + pCol->colFlags &= ~(COLFLAG_HASTYPE|COLFLAG_HASCOLL); + if( pCol->zCnName ){ + memcpy(&pCol->zCnName[n+1], zType, m+1); + pCol->colFlags |= COLFLAG_HASTYPE; + } + } + pColl = sqlite3ExprCollSeq(pParse, p); + if( pColl ){ + assert( pTab->pIndex==0 ); + sqlite3ColumnSetColl(db, pCol, pColl->zName); + } + } + pTab->szTabRow = 1; /* Any non-zero value works */ +} + +/* +** Given a SELECT statement, generate a Table structure that describes +** the result set of that SELECT. +*/ +Table *sqlite3ResultSetOfSelect(Parse *pParse, Select *pSelect, char aff){ + Table *pTab; + sqlite3 *db = pParse->db; + u64 savedFlags; + + savedFlags = db->flags; + db->flags &= ~(u64)SQLITE_FullColNames; + db->flags |= SQLITE_ShortColNames; + sqlite3SelectPrep(pParse, pSelect, 0); + db->flags = savedFlags; + if( pParse->nErr ) return 0; + while( pSelect->pPrior ) pSelect = pSelect->pPrior; + pTab = sqlite3DbMallocZero(db, sizeof(Table) ); + if( pTab==0 ){ + return 0; + } + pTab->nTabRef = 1; + pTab->zName = 0; + pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) ); + sqlite3ColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol); + sqlite3SubqueryColumnTypes(pParse, pTab, pSelect, aff); + pTab->iPKey = -1; + if( db->mallocFailed ){ + sqlite3DeleteTable(db, pTab); + return 0; + } + return pTab; +} + +/* +** Get a VDBE for the given parser context. Create a new one if necessary. +** If an error occurs, return NULL and leave a message in pParse. +*/ +Vdbe *sqlite3GetVdbe(Parse *pParse){ + if( pParse->pVdbe ){ + return pParse->pVdbe; + } + if( pParse->pToplevel==0 + && OptimizationEnabled(pParse->db,SQLITE_FactorOutConst) + ){ + pParse->okConstFactor = 1; + } + return sqlite3VdbeCreate(pParse); +} + + +/* +** Compute the iLimit and iOffset fields of the SELECT based on the +** pLimit expressions. pLimit->pLeft and pLimit->pRight hold the expressions +** that appear in the original SQL statement after the LIMIT and OFFSET +** keywords. Or NULL if those keywords are omitted. iLimit and iOffset +** are the integer memory register numbers for counters used to compute +** the limit and offset. If there is no limit and/or offset, then +** iLimit and iOffset are negative. +** +** This routine changes the values of iLimit and iOffset only if +** a limit or offset is defined by pLimit->pLeft and pLimit->pRight. iLimit +** and iOffset should have been preset to appropriate default values (zero) +** prior to calling this routine. +** +** The iOffset register (if it exists) is initialized to the value +** of the OFFSET. The iLimit register is initialized to LIMIT. Register +** iOffset+1 is initialized to LIMIT+OFFSET. +** +** Only if pLimit->pLeft!=0 do the limit registers get +** redefined. The UNION ALL operator uses this property to force +** the reuse of the same limit and offset registers across multiple +** SELECT statements. +*/ +static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){ + Vdbe *v = 0; + int iLimit = 0; + int iOffset; + int n; + Expr *pLimit = p->pLimit; + + if( p->iLimit ) return; + + /* + ** "LIMIT -1" always shows all rows. There is some + ** controversy about what the correct behavior should be. + ** The current implementation interprets "LIMIT 0" to mean + ** no rows. + */ + if( pLimit ){ + assert( pLimit->op==TK_LIMIT ); + assert( pLimit->pLeft!=0 ); + p->iLimit = iLimit = ++pParse->nMem; + v = sqlite3GetVdbe(pParse); + assert( v!=0 ); + if( sqlite3ExprIsInteger(pLimit->pLeft, &n) ){ + sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit); + VdbeComment((v, "LIMIT counter")); + if( n==0 ){ + sqlite3VdbeGoto(v, iBreak); + }else if( n>=0 && p->nSelectRow>sqlite3LogEst((u64)n) ){ + p->nSelectRow = sqlite3LogEst((u64)n); + p->selFlags |= SF_FixedLimit; + } + }else{ + sqlite3ExprCode(pParse, pLimit->pLeft, iLimit); + sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit); VdbeCoverage(v); + VdbeComment((v, "LIMIT counter")); + sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, iBreak); VdbeCoverage(v); + } + if( pLimit->pRight ){ + p->iOffset = iOffset = ++pParse->nMem; + pParse->nMem++; /* Allocate an extra register for limit+offset */ + sqlite3ExprCode(pParse, pLimit->pRight, iOffset); + sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v); + VdbeComment((v, "OFFSET counter")); + sqlite3VdbeAddOp3(v, OP_OffsetLimit, iLimit, iOffset+1, iOffset); + VdbeComment((v, "LIMIT+OFFSET")); + } + } +} + +#ifndef SQLITE_OMIT_COMPOUND_SELECT +/* +** Return the appropriate collating sequence for the iCol-th column of +** the result set for the compound-select statement "p". Return NULL if +** the column has no default collating sequence. +** +** The collating sequence for the compound select is taken from the +** left-most term of the select that has a collating sequence. +*/ +static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){ + CollSeq *pRet; + if( p->pPrior ){ + pRet = multiSelectCollSeq(pParse, p->pPrior, iCol); + }else{ + pRet = 0; + } + assert( iCol>=0 ); + /* iCol must be less than p->pEList->nExpr. Otherwise an error would + ** have been thrown during name resolution and we would not have gotten + ** this far */ + if( pRet==0 && ALWAYS(iCol<p->pEList->nExpr) ){ + pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr); + } + return pRet; +} + +/* +** The select statement passed as the second parameter is a compound SELECT +** with an ORDER BY clause. This function allocates and returns a KeyInfo +** structure suitable for implementing the ORDER BY. +** +** Space to hold the KeyInfo structure is obtained from malloc. The calling +** function is responsible for ensuring that this structure is eventually +** freed. +*/ +static KeyInfo *multiSelectOrderByKeyInfo(Parse *pParse, Select *p, int nExtra){ + ExprList *pOrderBy = p->pOrderBy; + int nOrderBy = ALWAYS(pOrderBy!=0) ? pOrderBy->nExpr : 0; + sqlite3 *db = pParse->db; + KeyInfo *pRet = sqlite3KeyInfoAlloc(db, nOrderBy+nExtra, 1); + if( pRet ){ + int i; + for(i=0; i<nOrderBy; i++){ + struct ExprList_item *pItem = &pOrderBy->a[i]; + Expr *pTerm = pItem->pExpr; + CollSeq *pColl; + + if( pTerm->flags & EP_Collate ){ + pColl = sqlite3ExprCollSeq(pParse, pTerm); + }else{ + pColl = multiSelectCollSeq(pParse, p, pItem->u.x.iOrderByCol-1); + if( pColl==0 ) pColl = db->pDfltColl; + pOrderBy->a[i].pExpr = + sqlite3ExprAddCollateString(pParse, pTerm, pColl->zName); + } + assert( sqlite3KeyInfoIsWriteable(pRet) ); + pRet->aColl[i] = pColl; + pRet->aSortFlags[i] = pOrderBy->a[i].fg.sortFlags; + } + } + + return pRet; +} + +#ifndef SQLITE_OMIT_CTE +/* +** This routine generates VDBE code to compute the content of a WITH RECURSIVE +** query of the form: +** +** <recursive-table> AS (<setup-query> UNION [ALL] <recursive-query>) +** \___________/ \_______________/ +** p->pPrior p +** +** +** There is exactly one reference to the recursive-table in the FROM clause +** of recursive-query, marked with the SrcList->a[].fg.isRecursive flag. +** +** The setup-query runs once to generate an initial set of rows that go +** into a Queue table. Rows are extracted from the Queue table one by +** one. Each row extracted from Queue is output to pDest. Then the single +** extracted row (now in the iCurrent table) becomes the content of the +** recursive-table for a recursive-query run. The output of the recursive-query +** is added back into the Queue table. Then another row is extracted from Queue +** and the iteration continues until the Queue table is empty. +** +** If the compound query operator is UNION then no duplicate rows are ever +** inserted into the Queue table. The iDistinct table keeps a copy of all rows +** that have ever been inserted into Queue and causes duplicates to be +** discarded. If the operator is UNION ALL, then duplicates are allowed. +** +** If the query has an ORDER BY, then entries in the Queue table are kept in +** ORDER BY order and the first entry is extracted for each cycle. Without +** an ORDER BY, the Queue table is just a FIFO. +** +** If a LIMIT clause is provided, then the iteration stops after LIMIT rows +** have been output to pDest. A LIMIT of zero means to output no rows and a +** negative LIMIT means to output all rows. If there is also an OFFSET clause +** with a positive value, then the first OFFSET outputs are discarded rather +** than being sent to pDest. The LIMIT count does not begin until after OFFSET +** rows have been skipped. +*/ +static void generateWithRecursiveQuery( + Parse *pParse, /* Parsing context */ + Select *p, /* The recursive SELECT to be coded */ + SelectDest *pDest /* What to do with query results */ +){ + SrcList *pSrc = p->pSrc; /* The FROM clause of the recursive query */ + int nCol = p->pEList->nExpr; /* Number of columns in the recursive table */ + Vdbe *v = pParse->pVdbe; /* The prepared statement under construction */ + Select *pSetup; /* The setup query */ + Select *pFirstRec; /* Left-most recursive term */ + int addrTop; /* Top of the loop */ + int addrCont, addrBreak; /* CONTINUE and BREAK addresses */ + int iCurrent = 0; /* The Current table */ + int regCurrent; /* Register holding Current table */ + int iQueue; /* The Queue table */ + int iDistinct = 0; /* To ensure unique results if UNION */ + int eDest = SRT_Fifo; /* How to write to Queue */ + SelectDest destQueue; /* SelectDest targeting the Queue table */ + int i; /* Loop counter */ + int rc; /* Result code */ + ExprList *pOrderBy; /* The ORDER BY clause */ + Expr *pLimit; /* Saved LIMIT and OFFSET */ + int regLimit, regOffset; /* Registers used by LIMIT and OFFSET */ + +#ifndef SQLITE_OMIT_WINDOWFUNC + if( p->pWin ){ + sqlite3ErrorMsg(pParse, "cannot use window functions in recursive queries"); + return; + } +#endif + + /* Obtain authorization to do a recursive query */ + if( sqlite3AuthCheck(pParse, SQLITE_RECURSIVE, 0, 0, 0) ) return; + + /* Process the LIMIT and OFFSET clauses, if they exist */ + addrBreak = sqlite3VdbeMakeLabel(pParse); + p->nSelectRow = 320; /* 4 billion rows */ + computeLimitRegisters(pParse, p, addrBreak); + pLimit = p->pLimit; + regLimit = p->iLimit; + regOffset = p->iOffset; + p->pLimit = 0; + p->iLimit = p->iOffset = 0; + pOrderBy = p->pOrderBy; + + /* Locate the cursor number of the Current table */ + for(i=0; ALWAYS(i<pSrc->nSrc); i++){ + if( pSrc->a[i].fg.isRecursive ){ + iCurrent = pSrc->a[i].iCursor; + break; + } + } + + /* Allocate cursors numbers for Queue and Distinct. The cursor number for + ** the Distinct table must be exactly one greater than Queue in order + ** for the SRT_DistFifo and SRT_DistQueue destinations to work. */ + iQueue = pParse->nTab++; + if( p->op==TK_UNION ){ + eDest = pOrderBy ? SRT_DistQueue : SRT_DistFifo; + iDistinct = pParse->nTab++; + }else{ + eDest = pOrderBy ? SRT_Queue : SRT_Fifo; + } + sqlite3SelectDestInit(&destQueue, eDest, iQueue); + + /* Allocate cursors for Current, Queue, and Distinct. */ + regCurrent = ++pParse->nMem; + sqlite3VdbeAddOp3(v, OP_OpenPseudo, iCurrent, regCurrent, nCol); + if( pOrderBy ){ + KeyInfo *pKeyInfo = multiSelectOrderByKeyInfo(pParse, p, 1); + sqlite3VdbeAddOp4(v, OP_OpenEphemeral, iQueue, pOrderBy->nExpr+2, 0, + (char*)pKeyInfo, P4_KEYINFO); + destQueue.pOrderBy = pOrderBy; + }else{ + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iQueue, nCol); + } + VdbeComment((v, "Queue table")); + if( iDistinct ){ + p->addrOpenEphm[0] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iDistinct, 0); + p->selFlags |= SF_UsesEphemeral; + } + + /* Detach the ORDER BY clause from the compound SELECT */ + p->pOrderBy = 0; + + /* Figure out how many elements of the compound SELECT are part of the + ** recursive query. Make sure no recursive elements use aggregate + ** functions. Mark the recursive elements as UNION ALL even if they + ** are really UNION because the distinctness will be enforced by the + ** iDistinct table. pFirstRec is left pointing to the left-most + ** recursive term of the CTE. + */ + for(pFirstRec=p; ALWAYS(pFirstRec!=0); pFirstRec=pFirstRec->pPrior){ + if( pFirstRec->selFlags & SF_Aggregate ){ + sqlite3ErrorMsg(pParse, "recursive aggregate queries not supported"); + goto end_of_recursive_query; + } + pFirstRec->op = TK_ALL; + if( (pFirstRec->pPrior->selFlags & SF_Recursive)==0 ) break; + } + + /* Store the results of the setup-query in Queue. */ + pSetup = pFirstRec->pPrior; + pSetup->pNext = 0; + ExplainQueryPlan((pParse, 1, "SETUP")); + rc = sqlite3Select(pParse, pSetup, &destQueue); + pSetup->pNext = p; + if( rc ) goto end_of_recursive_query; + + /* Find the next row in the Queue and output that row */ + addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak); VdbeCoverage(v); + + /* Transfer the next row in Queue over to Current */ + sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */ + if( pOrderBy ){ + sqlite3VdbeAddOp3(v, OP_Column, iQueue, pOrderBy->nExpr+1, regCurrent); + }else{ + sqlite3VdbeAddOp2(v, OP_RowData, iQueue, regCurrent); + } + sqlite3VdbeAddOp1(v, OP_Delete, iQueue); + + /* Output the single row in Current */ + addrCont = sqlite3VdbeMakeLabel(pParse); + codeOffset(v, regOffset, addrCont); + selectInnerLoop(pParse, p, iCurrent, + 0, 0, pDest, addrCont, addrBreak); + if( regLimit ){ + sqlite3VdbeAddOp2(v, OP_DecrJumpZero, regLimit, addrBreak); + VdbeCoverage(v); + } + sqlite3VdbeResolveLabel(v, addrCont); + + /* Execute the recursive SELECT taking the single row in Current as + ** the value for the recursive-table. Store the results in the Queue. + */ + pFirstRec->pPrior = 0; + ExplainQueryPlan((pParse, 1, "RECURSIVE STEP")); + sqlite3Select(pParse, p, &destQueue); + assert( pFirstRec->pPrior==0 ); + pFirstRec->pPrior = pSetup; + + /* Keep running the loop until the Queue is empty */ + sqlite3VdbeGoto(v, addrTop); + sqlite3VdbeResolveLabel(v, addrBreak); + +end_of_recursive_query: + sqlite3ExprListDelete(pParse->db, p->pOrderBy); + p->pOrderBy = pOrderBy; + p->pLimit = pLimit; + return; +} +#endif /* SQLITE_OMIT_CTE */ + +/* Forward references */ +static int multiSelectOrderBy( + Parse *pParse, /* Parsing context */ + Select *p, /* The right-most of SELECTs to be coded */ + SelectDest *pDest /* What to do with query results */ +); + +/* +** Handle the special case of a compound-select that originates from a +** VALUES clause. By handling this as a special case, we avoid deep +** recursion, and thus do not need to enforce the SQLITE_LIMIT_COMPOUND_SELECT +** on a VALUES clause. +** +** Because the Select object originates from a VALUES clause: +** (1) There is no LIMIT or OFFSET or else there is a LIMIT of exactly 1 +** (2) All terms are UNION ALL +** (3) There is no ORDER BY clause +** +** The "LIMIT of exactly 1" case of condition (1) comes about when a VALUES +** clause occurs within scalar expression (ex: "SELECT (VALUES(1),(2),(3))"). +** The sqlite3CodeSubselect will have added the LIMIT 1 clause in tht case. +** Since the limit is exactly 1, we only need to evaluate the left-most VALUES. +*/ +static int multiSelectValues( + Parse *pParse, /* Parsing context */ + Select *p, /* The right-most of SELECTs to be coded */ + SelectDest *pDest /* What to do with query results */ +){ + int nRow = 1; + int rc = 0; + int bShowAll = p->pLimit==0; + assert( p->selFlags & SF_MultiValue ); + do{ + assert( p->selFlags & SF_Values ); + assert( p->op==TK_ALL || (p->op==TK_SELECT && p->pPrior==0) ); + assert( p->pNext==0 || p->pEList->nExpr==p->pNext->pEList->nExpr ); +#ifndef SQLITE_OMIT_WINDOWFUNC + if( p->pWin ) return -1; +#endif + if( p->pPrior==0 ) break; + assert( p->pPrior->pNext==p ); + p = p->pPrior; + nRow += bShowAll; + }while(1); + ExplainQueryPlan((pParse, 0, "SCAN %d CONSTANT ROW%s", nRow, + nRow==1 ? "" : "S")); + while( p ){ + selectInnerLoop(pParse, p, -1, 0, 0, pDest, 1, 1); + if( !bShowAll ) break; + p->nSelectRow = nRow; + p = p->pNext; + } + return rc; +} + +/* +** Return true if the SELECT statement which is known to be the recursive +** part of a recursive CTE still has its anchor terms attached. If the +** anchor terms have already been removed, then return false. +*/ +static int hasAnchor(Select *p){ + while( p && (p->selFlags & SF_Recursive)!=0 ){ p = p->pPrior; } + return p!=0; +} + +/* +** This routine is called to process a compound query form from +** two or more separate queries using UNION, UNION ALL, EXCEPT, or +** INTERSECT +** +** "p" points to the right-most of the two queries. the query on the +** left is p->pPrior. The left query could also be a compound query +** in which case this routine will be called recursively. +** +** The results of the total query are to be written into a destination +** of type eDest with parameter iParm. +** +** Example 1: Consider a three-way compound SQL statement. +** +** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3 +** +** This statement is parsed up as follows: +** +** SELECT c FROM t3 +** | +** `-----> SELECT b FROM t2 +** | +** `------> SELECT a FROM t1 +** +** The arrows in the diagram above represent the Select.pPrior pointer. +** So if this routine is called with p equal to the t3 query, then +** pPrior will be the t2 query. p->op will be TK_UNION in this case. +** +** Notice that because of the way SQLite parses compound SELECTs, the +** individual selects always group from left to right. +*/ +static int multiSelect( + Parse *pParse, /* Parsing context */ + Select *p, /* The right-most of SELECTs to be coded */ + SelectDest *pDest /* What to do with query results */ +){ + int rc = SQLITE_OK; /* Success code from a subroutine */ + Select *pPrior; /* Another SELECT immediately to our left */ + Vdbe *v; /* Generate code to this VDBE */ + SelectDest dest; /* Alternative data destination */ + Select *pDelete = 0; /* Chain of simple selects to delete */ + sqlite3 *db; /* Database connection */ + + /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only + ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT. + */ + assert( p && p->pPrior ); /* Calling function guarantees this much */ + assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION ); + assert( p->selFlags & SF_Compound ); + db = pParse->db; + pPrior = p->pPrior; + dest = *pDest; + assert( pPrior->pOrderBy==0 ); + assert( pPrior->pLimit==0 ); + + v = sqlite3GetVdbe(pParse); + assert( v!=0 ); /* The VDBE already created by calling function */ + + /* Create the destination temporary table if necessary + */ + if( dest.eDest==SRT_EphemTab ){ + assert( p->pEList ); + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iSDParm, p->pEList->nExpr); + dest.eDest = SRT_Table; + } + + /* Special handling for a compound-select that originates as a VALUES clause. + */ + if( p->selFlags & SF_MultiValue ){ + rc = multiSelectValues(pParse, p, &dest); + if( rc>=0 ) goto multi_select_end; + rc = SQLITE_OK; + } + + /* Make sure all SELECTs in the statement have the same number of elements + ** in their result sets. + */ + assert( p->pEList && pPrior->pEList ); + assert( p->pEList->nExpr==pPrior->pEList->nExpr ); + +#ifndef SQLITE_OMIT_CTE + if( (p->selFlags & SF_Recursive)!=0 && hasAnchor(p) ){ + generateWithRecursiveQuery(pParse, p, &dest); + }else +#endif + + /* Compound SELECTs that have an ORDER BY clause are handled separately. + */ + if( p->pOrderBy ){ + return multiSelectOrderBy(pParse, p, pDest); + }else{ + +#ifndef SQLITE_OMIT_EXPLAIN + if( pPrior->pPrior==0 ){ + ExplainQueryPlan((pParse, 1, "COMPOUND QUERY")); + ExplainQueryPlan((pParse, 1, "LEFT-MOST SUBQUERY")); + } +#endif + + /* Generate code for the left and right SELECT statements. + */ + switch( p->op ){ + case TK_ALL: { + int addr = 0; + int nLimit = 0; /* Initialize to suppress harmless compiler warning */ + assert( !pPrior->pLimit ); + pPrior->iLimit = p->iLimit; + pPrior->iOffset = p->iOffset; + pPrior->pLimit = p->pLimit; + TREETRACE(0x200, pParse, p, ("multiSelect UNION ALL left...\n")); + rc = sqlite3Select(pParse, pPrior, &dest); + pPrior->pLimit = 0; + if( rc ){ + goto multi_select_end; + } + p->pPrior = 0; + p->iLimit = pPrior->iLimit; + p->iOffset = pPrior->iOffset; + if( p->iLimit ){ + addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v); + VdbeComment((v, "Jump ahead if LIMIT reached")); + if( p->iOffset ){ + sqlite3VdbeAddOp3(v, OP_OffsetLimit, + p->iLimit, p->iOffset+1, p->iOffset); + } + } + ExplainQueryPlan((pParse, 1, "UNION ALL")); + TREETRACE(0x200, pParse, p, ("multiSelect UNION ALL right...\n")); + rc = sqlite3Select(pParse, p, &dest); + testcase( rc!=SQLITE_OK ); + pDelete = p->pPrior; + p->pPrior = pPrior; + p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow); + if( p->pLimit + && sqlite3ExprIsInteger(p->pLimit->pLeft, &nLimit) + && nLimit>0 && p->nSelectRow > sqlite3LogEst((u64)nLimit) + ){ + p->nSelectRow = sqlite3LogEst((u64)nLimit); + } + if( addr ){ + sqlite3VdbeJumpHere(v, addr); + } + break; + } + case TK_EXCEPT: + case TK_UNION: { + int unionTab; /* Cursor number of the temp table holding result */ + u8 op = 0; /* One of the SRT_ operations to apply to self */ + int priorOp; /* The SRT_ operation to apply to prior selects */ + Expr *pLimit; /* Saved values of p->nLimit */ + int addr; + SelectDest uniondest; + + testcase( p->op==TK_EXCEPT ); + testcase( p->op==TK_UNION ); + priorOp = SRT_Union; + if( dest.eDest==priorOp ){ + /* We can reuse a temporary table generated by a SELECT to our + ** right. + */ + assert( p->pLimit==0 ); /* Not allowed on leftward elements */ + unionTab = dest.iSDParm; + }else{ + /* We will need to create our own temporary table to hold the + ** intermediate results. + */ + unionTab = pParse->nTab++; + assert( p->pOrderBy==0 ); + addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0); + assert( p->addrOpenEphm[0] == -1 ); + p->addrOpenEphm[0] = addr; + findRightmost(p)->selFlags |= SF_UsesEphemeral; + assert( p->pEList ); + } + + + /* Code the SELECT statements to our left + */ + assert( !pPrior->pOrderBy ); + sqlite3SelectDestInit(&uniondest, priorOp, unionTab); + TREETRACE(0x200, pParse, p, ("multiSelect EXCEPT/UNION left...\n")); + rc = sqlite3Select(pParse, pPrior, &uniondest); + if( rc ){ + goto multi_select_end; + } + + /* Code the current SELECT statement + */ + if( p->op==TK_EXCEPT ){ + op = SRT_Except; + }else{ + assert( p->op==TK_UNION ); + op = SRT_Union; + } + p->pPrior = 0; + pLimit = p->pLimit; + p->pLimit = 0; + uniondest.eDest = op; + ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE", + sqlite3SelectOpName(p->op))); + TREETRACE(0x200, pParse, p, ("multiSelect EXCEPT/UNION right...\n")); + rc = sqlite3Select(pParse, p, &uniondest); + testcase( rc!=SQLITE_OK ); + assert( p->pOrderBy==0 ); + pDelete = p->pPrior; + p->pPrior = pPrior; + p->pOrderBy = 0; + if( p->op==TK_UNION ){ + p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow); + } + sqlite3ExprDelete(db, p->pLimit); + p->pLimit = pLimit; + p->iLimit = 0; + p->iOffset = 0; + + /* Convert the data in the temporary table into whatever form + ** it is that we currently need. + */ + assert( unionTab==dest.iSDParm || dest.eDest!=priorOp ); + assert( p->pEList || db->mallocFailed ); + if( dest.eDest!=priorOp && db->mallocFailed==0 ){ + int iCont, iBreak, iStart; + iBreak = sqlite3VdbeMakeLabel(pParse); + iCont = sqlite3VdbeMakeLabel(pParse); + computeLimitRegisters(pParse, p, iBreak); + sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak); VdbeCoverage(v); + iStart = sqlite3VdbeCurrentAddr(v); + selectInnerLoop(pParse, p, unionTab, + 0, 0, &dest, iCont, iBreak); + sqlite3VdbeResolveLabel(v, iCont); + sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart); VdbeCoverage(v); + sqlite3VdbeResolveLabel(v, iBreak); + sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0); + } + break; + } + default: assert( p->op==TK_INTERSECT ); { + int tab1, tab2; + int iCont, iBreak, iStart; + Expr *pLimit; + int addr; + SelectDest intersectdest; + int r1; + + /* INTERSECT is different from the others since it requires + ** two temporary tables. Hence it has its own case. Begin + ** by allocating the tables we will need. + */ + tab1 = pParse->nTab++; + tab2 = pParse->nTab++; + assert( p->pOrderBy==0 ); + + addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0); + assert( p->addrOpenEphm[0] == -1 ); + p->addrOpenEphm[0] = addr; + findRightmost(p)->selFlags |= SF_UsesEphemeral; + assert( p->pEList ); + + /* Code the SELECTs to our left into temporary table "tab1". + */ + sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1); + TREETRACE(0x400, pParse, p, ("multiSelect INTERSECT left...\n")); + rc = sqlite3Select(pParse, pPrior, &intersectdest); + if( rc ){ + goto multi_select_end; + } + + /* Code the current SELECT into temporary table "tab2" + */ + addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0); + assert( p->addrOpenEphm[1] == -1 ); + p->addrOpenEphm[1] = addr; + p->pPrior = 0; + pLimit = p->pLimit; + p->pLimit = 0; + intersectdest.iSDParm = tab2; + ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE", + sqlite3SelectOpName(p->op))); + TREETRACE(0x400, pParse, p, ("multiSelect INTERSECT right...\n")); + rc = sqlite3Select(pParse, p, &intersectdest); + testcase( rc!=SQLITE_OK ); + pDelete = p->pPrior; + p->pPrior = pPrior; + if( p->nSelectRow>pPrior->nSelectRow ){ + p->nSelectRow = pPrior->nSelectRow; + } + sqlite3ExprDelete(db, p->pLimit); + p->pLimit = pLimit; + + /* Generate code to take the intersection of the two temporary + ** tables. + */ + if( rc ) break; + assert( p->pEList ); + iBreak = sqlite3VdbeMakeLabel(pParse); + iCont = sqlite3VdbeMakeLabel(pParse); + computeLimitRegisters(pParse, p, iBreak); + sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak); VdbeCoverage(v); + r1 = sqlite3GetTempReg(pParse); + iStart = sqlite3VdbeAddOp2(v, OP_RowData, tab1, r1); + sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0); + VdbeCoverage(v); + sqlite3ReleaseTempReg(pParse, r1); + selectInnerLoop(pParse, p, tab1, + 0, 0, &dest, iCont, iBreak); + sqlite3VdbeResolveLabel(v, iCont); + sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart); VdbeCoverage(v); + sqlite3VdbeResolveLabel(v, iBreak); + sqlite3VdbeAddOp2(v, OP_Close, tab2, 0); + sqlite3VdbeAddOp2(v, OP_Close, tab1, 0); + break; + } + } + + #ifndef SQLITE_OMIT_EXPLAIN + if( p->pNext==0 ){ + ExplainQueryPlanPop(pParse); + } + #endif + } + if( pParse->nErr ) goto multi_select_end; + + /* Compute collating sequences used by + ** temporary tables needed to implement the compound select. + ** Attach the KeyInfo structure to all temporary tables. + ** + ** This section is run by the right-most SELECT statement only. + ** SELECT statements to the left always skip this part. The right-most + ** SELECT might also skip this part if it has no ORDER BY clause and + ** no temp tables are required. + */ + if( p->selFlags & SF_UsesEphemeral ){ + int i; /* Loop counter */ + KeyInfo *pKeyInfo; /* Collating sequence for the result set */ + Select *pLoop; /* For looping through SELECT statements */ + CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */ + int nCol; /* Number of columns in result set */ + + assert( p->pNext==0 ); + assert( p->pEList!=0 ); + nCol = p->pEList->nExpr; + pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1); + if( !pKeyInfo ){ + rc = SQLITE_NOMEM_BKPT; + goto multi_select_end; + } + for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){ + *apColl = multiSelectCollSeq(pParse, p, i); + if( 0==*apColl ){ + *apColl = db->pDfltColl; + } + } + + for(pLoop=p; pLoop; pLoop=pLoop->pPrior){ + for(i=0; i<2; i++){ + int addr = pLoop->addrOpenEphm[i]; + if( addr<0 ){ + /* If [0] is unused then [1] is also unused. So we can + ** always safely abort as soon as the first unused slot is found */ + assert( pLoop->addrOpenEphm[1]<0 ); + break; + } + sqlite3VdbeChangeP2(v, addr, nCol); + sqlite3VdbeChangeP4(v, addr, (char*)sqlite3KeyInfoRef(pKeyInfo), + P4_KEYINFO); + pLoop->addrOpenEphm[i] = -1; + } + } + sqlite3KeyInfoUnref(pKeyInfo); + } + +multi_select_end: + pDest->iSdst = dest.iSdst; + pDest->nSdst = dest.nSdst; + if( pDelete ){ + sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pDelete); + } + return rc; +} +#endif /* SQLITE_OMIT_COMPOUND_SELECT */ + +/* +** Error message for when two or more terms of a compound select have different +** size result sets. +*/ +void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p){ + if( p->selFlags & SF_Values ){ + sqlite3ErrorMsg(pParse, "all VALUES must have the same number of terms"); + }else{ + sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s" + " do not have the same number of result columns", + sqlite3SelectOpName(p->op)); + } +} + +/* +** Code an output subroutine for a coroutine implementation of a +** SELECT statement. +** +** The data to be output is contained in pIn->iSdst. There are +** pIn->nSdst columns to be output. pDest is where the output should +** be sent. +** +** regReturn is the number of the register holding the subroutine +** return address. +** +** If regPrev>0 then it is the first register in a vector that +** records the previous output. mem[regPrev] is a flag that is false +** if there has been no previous output. If regPrev>0 then code is +** generated to suppress duplicates. pKeyInfo is used for comparing +** keys. +** +** If the LIMIT found in p->iLimit is reached, jump immediately to +** iBreak. +*/ +static int generateOutputSubroutine( + Parse *pParse, /* Parsing context */ + Select *p, /* The SELECT statement */ + SelectDest *pIn, /* Coroutine supplying data */ + SelectDest *pDest, /* Where to send the data */ + int regReturn, /* The return address register */ + int regPrev, /* Previous result register. No uniqueness if 0 */ + KeyInfo *pKeyInfo, /* For comparing with previous entry */ + int iBreak /* Jump here if we hit the LIMIT */ +){ + Vdbe *v = pParse->pVdbe; + int iContinue; + int addr; + + addr = sqlite3VdbeCurrentAddr(v); + iContinue = sqlite3VdbeMakeLabel(pParse); + + /* Suppress duplicates for UNION, EXCEPT, and INTERSECT + */ + if( regPrev ){ + int addr1, addr2; + addr1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev); VdbeCoverage(v); + addr2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst, + (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO); + sqlite3VdbeAddOp3(v, OP_Jump, addr2+2, iContinue, addr2+2); VdbeCoverage(v); + sqlite3VdbeJumpHere(v, addr1); + sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1); + sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev); + } + if( pParse->db->mallocFailed ) return 0; + + /* Suppress the first OFFSET entries if there is an OFFSET clause + */ + codeOffset(v, p->iOffset, iContinue); + + assert( pDest->eDest!=SRT_Exists ); + assert( pDest->eDest!=SRT_Table ); + switch( pDest->eDest ){ + /* Store the result as data using a unique key. + */ + case SRT_EphemTab: { + int r1 = sqlite3GetTempReg(pParse); + int r2 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, r1); + sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iSDParm, r2); + sqlite3VdbeAddOp3(v, OP_Insert, pDest->iSDParm, r1, r2); + sqlite3VdbeChangeP5(v, OPFLAG_APPEND); + sqlite3ReleaseTempReg(pParse, r2); + sqlite3ReleaseTempReg(pParse, r1); + break; + } + +#ifndef SQLITE_OMIT_SUBQUERY + /* If we are creating a set for an "expr IN (SELECT ...)". + */ + case SRT_Set: { + int r1; + testcase( pIn->nSdst>1 ); + r1 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, + r1, pDest->zAffSdst, pIn->nSdst); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pDest->iSDParm, r1, + pIn->iSdst, pIn->nSdst); + sqlite3ReleaseTempReg(pParse, r1); + break; + } + + /* If this is a scalar select that is part of an expression, then + ** store the results in the appropriate memory cell and break out + ** of the scan loop. Note that the select might return multiple columns + ** if it is the RHS of a row-value IN operator. + */ + case SRT_Mem: { + testcase( pIn->nSdst>1 ); + sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, pIn->nSdst); + /* The LIMIT clause will jump out of the loop for us */ + break; + } +#endif /* #ifndef SQLITE_OMIT_SUBQUERY */ + + /* The results are stored in a sequence of registers + ** starting at pDest->iSdst. Then the co-routine yields. + */ + case SRT_Coroutine: { + if( pDest->iSdst==0 ){ + pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst); + pDest->nSdst = pIn->nSdst; + } + sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pIn->nSdst); + sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm); + break; + } + + /* If none of the above, then the result destination must be + ** SRT_Output. This routine is never called with any other + ** destination other than the ones handled above or SRT_Output. + ** + ** For SRT_Output, results are stored in a sequence of registers. + ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to + ** return the next row of result. + */ + default: { + assert( pDest->eDest==SRT_Output ); + sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst); + break; + } + } + + /* Jump to the end of the loop if the LIMIT is reached. + */ + if( p->iLimit ){ + sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v); + } + + /* Generate the subroutine return + */ + sqlite3VdbeResolveLabel(v, iContinue); + sqlite3VdbeAddOp1(v, OP_Return, regReturn); + + return addr; +} + +/* +** Alternative compound select code generator for cases when there +** is an ORDER BY clause. +** +** We assume a query of the following form: +** +** <selectA> <operator> <selectB> ORDER BY <orderbylist> +** +** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT. The idea +** is to code both <selectA> and <selectB> with the ORDER BY clause as +** co-routines. Then run the co-routines in parallel and merge the results +** into the output. In addition to the two coroutines (called selectA and +** selectB) there are 7 subroutines: +** +** outA: Move the output of the selectA coroutine into the output +** of the compound query. +** +** outB: Move the output of the selectB coroutine into the output +** of the compound query. (Only generated for UNION and +** UNION ALL. EXCEPT and INSERTSECT never output a row that +** appears only in B.) +** +** AltB: Called when there is data from both coroutines and A<B. +** +** AeqB: Called when there is data from both coroutines and A==B. +** +** AgtB: Called when there is data from both coroutines and A>B. +** +** EofA: Called when data is exhausted from selectA. +** +** EofB: Called when data is exhausted from selectB. +** +** The implementation of the latter five subroutines depend on which +** <operator> is used: +** +** +** UNION ALL UNION EXCEPT INTERSECT +** ------------- ----------------- -------------- ----------------- +** AltB: outA, nextA outA, nextA outA, nextA nextA +** +** AeqB: outA, nextA nextA nextA outA, nextA +** +** AgtB: outB, nextB outB, nextB nextB nextB +** +** EofA: outB, nextB outB, nextB halt halt +** +** EofB: outA, nextA outA, nextA outA, nextA halt +** +** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA +** causes an immediate jump to EofA and an EOF on B following nextB causes +** an immediate jump to EofB. Within EofA and EofB, and EOF on entry or +** following nextX causes a jump to the end of the select processing. +** +** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled +** within the output subroutine. The regPrev register set holds the previously +** output value. A comparison is made against this value and the output +** is skipped if the next results would be the same as the previous. +** +** The implementation plan is to implement the two coroutines and seven +** subroutines first, then put the control logic at the bottom. Like this: +** +** goto Init +** coA: coroutine for left query (A) +** coB: coroutine for right query (B) +** outA: output one row of A +** outB: output one row of B (UNION and UNION ALL only) +** EofA: ... +** EofB: ... +** AltB: ... +** AeqB: ... +** AgtB: ... +** Init: initialize coroutine registers +** yield coA +** if eof(A) goto EofA +** yield coB +** if eof(B) goto EofB +** Cmpr: Compare A, B +** Jump AltB, AeqB, AgtB +** End: ... +** +** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not +** actually called using Gosub and they do not Return. EofA and EofB loop +** until all data is exhausted then jump to the "end" label. AltB, AeqB, +** and AgtB jump to either L2 or to one of EofA or EofB. +*/ +#ifndef SQLITE_OMIT_COMPOUND_SELECT +static int multiSelectOrderBy( + Parse *pParse, /* Parsing context */ + Select *p, /* The right-most of SELECTs to be coded */ + SelectDest *pDest /* What to do with query results */ +){ + int i, j; /* Loop counters */ + Select *pPrior; /* Another SELECT immediately to our left */ + Select *pSplit; /* Left-most SELECT in the right-hand group */ + int nSelect; /* Number of SELECT statements in the compound */ + Vdbe *v; /* Generate code to this VDBE */ + SelectDest destA; /* Destination for coroutine A */ + SelectDest destB; /* Destination for coroutine B */ + int regAddrA; /* Address register for select-A coroutine */ + int regAddrB; /* Address register for select-B coroutine */ + int addrSelectA; /* Address of the select-A coroutine */ + int addrSelectB; /* Address of the select-B coroutine */ + int regOutA; /* Address register for the output-A subroutine */ + int regOutB; /* Address register for the output-B subroutine */ + int addrOutA; /* Address of the output-A subroutine */ + int addrOutB = 0; /* Address of the output-B subroutine */ + int addrEofA; /* Address of the select-A-exhausted subroutine */ + int addrEofA_noB; /* Alternate addrEofA if B is uninitialized */ + int addrEofB; /* Address of the select-B-exhausted subroutine */ + int addrAltB; /* Address of the A<B subroutine */ + int addrAeqB; /* Address of the A==B subroutine */ + int addrAgtB; /* Address of the A>B subroutine */ + int regLimitA; /* Limit register for select-A */ + int regLimitB; /* Limit register for select-A */ + int regPrev; /* A range of registers to hold previous output */ + int savedLimit; /* Saved value of p->iLimit */ + int savedOffset; /* Saved value of p->iOffset */ + int labelCmpr; /* Label for the start of the merge algorithm */ + int labelEnd; /* Label for the end of the overall SELECT stmt */ + int addr1; /* Jump instructions that get retargeted */ + int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */ + KeyInfo *pKeyDup = 0; /* Comparison information for duplicate removal */ + KeyInfo *pKeyMerge; /* Comparison information for merging rows */ + sqlite3 *db; /* Database connection */ + ExprList *pOrderBy; /* The ORDER BY clause */ + int nOrderBy; /* Number of terms in the ORDER BY clause */ + u32 *aPermute; /* Mapping from ORDER BY terms to result set columns */ + + assert( p->pOrderBy!=0 ); + assert( pKeyDup==0 ); /* "Managed" code needs this. Ticket #3382. */ + db = pParse->db; + v = pParse->pVdbe; + assert( v!=0 ); /* Already thrown the error if VDBE alloc failed */ + labelEnd = sqlite3VdbeMakeLabel(pParse); + labelCmpr = sqlite3VdbeMakeLabel(pParse); + + + /* Patch up the ORDER BY clause + */ + op = p->op; + assert( p->pPrior->pOrderBy==0 ); + pOrderBy = p->pOrderBy; + assert( pOrderBy ); + nOrderBy = pOrderBy->nExpr; + + /* For operators other than UNION ALL we have to make sure that + ** the ORDER BY clause covers every term of the result set. Add + ** terms to the ORDER BY clause as necessary. + */ + if( op!=TK_ALL ){ + for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){ + struct ExprList_item *pItem; + for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){ + assert( pItem!=0 ); + assert( pItem->u.x.iOrderByCol>0 ); + if( pItem->u.x.iOrderByCol==i ) break; + } + if( j==nOrderBy ){ + Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0); + if( pNew==0 ) return SQLITE_NOMEM_BKPT; + pNew->flags |= EP_IntValue; + pNew->u.iValue = i; + p->pOrderBy = pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew); + if( pOrderBy ) pOrderBy->a[nOrderBy++].u.x.iOrderByCol = (u16)i; + } + } + } + + /* Compute the comparison permutation and keyinfo that is used with + ** the permutation used to determine if the next + ** row of results comes from selectA or selectB. Also add explicit + ** collations to the ORDER BY clause terms so that when the subqueries + ** to the right and the left are evaluated, they use the correct + ** collation. + */ + aPermute = sqlite3DbMallocRawNN(db, sizeof(u32)*(nOrderBy + 1)); + if( aPermute ){ + struct ExprList_item *pItem; + aPermute[0] = nOrderBy; + for(i=1, pItem=pOrderBy->a; i<=nOrderBy; i++, pItem++){ + assert( pItem!=0 ); + assert( pItem->u.x.iOrderByCol>0 ); + assert( pItem->u.x.iOrderByCol<=p->pEList->nExpr ); + aPermute[i] = pItem->u.x.iOrderByCol - 1; + } + pKeyMerge = multiSelectOrderByKeyInfo(pParse, p, 1); + }else{ + pKeyMerge = 0; + } + + /* Allocate a range of temporary registers and the KeyInfo needed + ** for the logic that removes duplicate result rows when the + ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL). + */ + if( op==TK_ALL ){ + regPrev = 0; + }else{ + int nExpr = p->pEList->nExpr; + assert( nOrderBy>=nExpr || db->mallocFailed ); + regPrev = pParse->nMem+1; + pParse->nMem += nExpr+1; + sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev); + pKeyDup = sqlite3KeyInfoAlloc(db, nExpr, 1); + if( pKeyDup ){ + assert( sqlite3KeyInfoIsWriteable(pKeyDup) ); + for(i=0; i<nExpr; i++){ + pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i); + pKeyDup->aSortFlags[i] = 0; + } + } + } + + /* Separate the left and the right query from one another + */ + nSelect = 1; + if( (op==TK_ALL || op==TK_UNION) + && OptimizationEnabled(db, SQLITE_BalancedMerge) + ){ + for(pSplit=p; pSplit->pPrior!=0 && pSplit->op==op; pSplit=pSplit->pPrior){ + nSelect++; + assert( pSplit->pPrior->pNext==pSplit ); + } + } + if( nSelect<=3 ){ + pSplit = p; + }else{ + pSplit = p; + for(i=2; i<nSelect; i+=2){ pSplit = pSplit->pPrior; } + } + pPrior = pSplit->pPrior; + assert( pPrior!=0 ); + pSplit->pPrior = 0; + pPrior->pNext = 0; + assert( p->pOrderBy == pOrderBy ); + assert( pOrderBy!=0 || db->mallocFailed ); + pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0); + sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER"); + sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER"); + + /* Compute the limit registers */ + computeLimitRegisters(pParse, p, labelEnd); + if( p->iLimit && op==TK_ALL ){ + regLimitA = ++pParse->nMem; + regLimitB = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit, + regLimitA); + sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB); + }else{ + regLimitA = regLimitB = 0; + } + sqlite3ExprDelete(db, p->pLimit); + p->pLimit = 0; + + regAddrA = ++pParse->nMem; + regAddrB = ++pParse->nMem; + regOutA = ++pParse->nMem; + regOutB = ++pParse->nMem; + sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA); + sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB); + + ExplainQueryPlan((pParse, 1, "MERGE (%s)", sqlite3SelectOpName(p->op))); + + /* Generate a coroutine to evaluate the SELECT statement to the + ** left of the compound operator - the "A" select. + */ + addrSelectA = sqlite3VdbeCurrentAddr(v) + 1; + addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrA, 0, addrSelectA); + VdbeComment((v, "left SELECT")); + pPrior->iLimit = regLimitA; + ExplainQueryPlan((pParse, 1, "LEFT")); + sqlite3Select(pParse, pPrior, &destA); + sqlite3VdbeEndCoroutine(v, regAddrA); + sqlite3VdbeJumpHere(v, addr1); + + /* Generate a coroutine to evaluate the SELECT statement on + ** the right - the "B" select + */ + addrSelectB = sqlite3VdbeCurrentAddr(v) + 1; + addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrB, 0, addrSelectB); + VdbeComment((v, "right SELECT")); + savedLimit = p->iLimit; + savedOffset = p->iOffset; + p->iLimit = regLimitB; + p->iOffset = 0; + ExplainQueryPlan((pParse, 1, "RIGHT")); + sqlite3Select(pParse, p, &destB); + p->iLimit = savedLimit; + p->iOffset = savedOffset; + sqlite3VdbeEndCoroutine(v, regAddrB); + + /* Generate a subroutine that outputs the current row of the A + ** select as the next output row of the compound select. + */ + VdbeNoopComment((v, "Output routine for A")); + addrOutA = generateOutputSubroutine(pParse, + p, &destA, pDest, regOutA, + regPrev, pKeyDup, labelEnd); + + /* Generate a subroutine that outputs the current row of the B + ** select as the next output row of the compound select. + */ + if( op==TK_ALL || op==TK_UNION ){ + VdbeNoopComment((v, "Output routine for B")); + addrOutB = generateOutputSubroutine(pParse, + p, &destB, pDest, regOutB, + regPrev, pKeyDup, labelEnd); + } + sqlite3KeyInfoUnref(pKeyDup); + + /* Generate a subroutine to run when the results from select A + ** are exhausted and only data in select B remains. + */ + if( op==TK_EXCEPT || op==TK_INTERSECT ){ + addrEofA_noB = addrEofA = labelEnd; + }else{ + VdbeNoopComment((v, "eof-A subroutine")); + addrEofA = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB); + addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd); + VdbeCoverage(v); + sqlite3VdbeGoto(v, addrEofA); + p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow); + } + + /* Generate a subroutine to run when the results from select B + ** are exhausted and only data in select A remains. + */ + if( op==TK_INTERSECT ){ + addrEofB = addrEofA; + if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow; + }else{ + VdbeNoopComment((v, "eof-B subroutine")); + addrEofB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA); + sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, labelEnd); VdbeCoverage(v); + sqlite3VdbeGoto(v, addrEofB); + } + + /* Generate code to handle the case of A<B + */ + VdbeNoopComment((v, "A-lt-B subroutine")); + addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA); + sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v); + sqlite3VdbeGoto(v, labelCmpr); + + /* Generate code to handle the case of A==B + */ + if( op==TK_ALL ){ + addrAeqB = addrAltB; + }else if( op==TK_INTERSECT ){ + addrAeqB = addrAltB; + addrAltB++; + }else{ + VdbeNoopComment((v, "A-eq-B subroutine")); + addrAeqB = + sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v); + sqlite3VdbeGoto(v, labelCmpr); + } + + /* Generate code to handle the case of A>B + */ + VdbeNoopComment((v, "A-gt-B subroutine")); + addrAgtB = sqlite3VdbeCurrentAddr(v); + if( op==TK_ALL || op==TK_UNION ){ + sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB); + } + sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v); + sqlite3VdbeGoto(v, labelCmpr); + + /* This code runs once to initialize everything. + */ + sqlite3VdbeJumpHere(v, addr1); + sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA_noB); VdbeCoverage(v); + sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v); + + /* Implement the main merge loop + */ + sqlite3VdbeResolveLabel(v, labelCmpr); + sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY); + sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy, + (char*)pKeyMerge, P4_KEYINFO); + sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE); + sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB); VdbeCoverage(v); + + /* Jump to the this point in order to terminate the query. + */ + sqlite3VdbeResolveLabel(v, labelEnd); + + /* Make arrangements to free the 2nd and subsequent arms of the compound + ** after the parse has finished */ + if( pSplit->pPrior ){ + sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pSplit->pPrior); + } + pSplit->pPrior = pPrior; + pPrior->pNext = pSplit; + sqlite3ExprListDelete(db, pPrior->pOrderBy); + pPrior->pOrderBy = 0; + + /*** TBD: Insert subroutine calls to close cursors on incomplete + **** subqueries ****/ + ExplainQueryPlanPop(pParse); + return pParse->nErr!=0; +} +#endif + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) + +/* An instance of the SubstContext object describes an substitution edit +** to be performed on a parse tree. +** +** All references to columns in table iTable are to be replaced by corresponding +** expressions in pEList. +** +** ## About "isOuterJoin": +** +** The isOuterJoin column indicates that the replacement will occur into a +** position in the parent that NULL-able due to an OUTER JOIN. Either the +** target slot in the parent is the right operand of a LEFT JOIN, or one of +** the left operands of a RIGHT JOIN. In either case, we need to potentially +** bypass the substituted expression with OP_IfNullRow. +** +** Suppose the original expression is an integer constant. Even though the table +** has the nullRow flag set, because the expression is an integer constant, +** it will not be NULLed out. So instead, we insert an OP_IfNullRow opcode +** that checks to see if the nullRow flag is set on the table. If the nullRow +** flag is set, then the value in the register is set to NULL and the original +** expression is bypassed. If the nullRow flag is not set, then the original +** expression runs to populate the register. +** +** Example where this is needed: +** +** CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT); +** CREATE TABLE t2(x INT UNIQUE); +** +** SELECT a,b,m,x FROM t1 LEFT JOIN (SELECT 59 AS m,x FROM t2) ON b=x; +** +** When the subquery on the right side of the LEFT JOIN is flattened, we +** have to add OP_IfNullRow in front of the OP_Integer that implements the +** "m" value of the subquery so that a NULL will be loaded instead of 59 +** when processing a non-matched row of the left. +*/ +typedef struct SubstContext { + Parse *pParse; /* The parsing context */ + int iTable; /* Replace references to this table */ + int iNewTable; /* New table number */ + int isOuterJoin; /* Add TK_IF_NULL_ROW opcodes on each replacement */ + ExprList *pEList; /* Replacement expressions */ + ExprList *pCList; /* Collation sequences for replacement expr */ +} SubstContext; + +/* Forward Declarations */ +static void substExprList(SubstContext*, ExprList*); +static void substSelect(SubstContext*, Select*, int); + +/* +** Scan through the expression pExpr. Replace every reference to +** a column in table number iTable with a copy of the iColumn-th +** entry in pEList. (But leave references to the ROWID column +** unchanged.) +** +** This routine is part of the flattening procedure. A subquery +** whose result set is defined by pEList appears as entry in the +** FROM clause of a SELECT such that the VDBE cursor assigned to that +** FORM clause entry is iTable. This routine makes the necessary +** changes to pExpr so that it refers directly to the source table +** of the subquery rather the result set of the subquery. +*/ +static Expr *substExpr( + SubstContext *pSubst, /* Description of the substitution */ + Expr *pExpr /* Expr in which substitution occurs */ +){ + if( pExpr==0 ) return 0; + if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON) + && pExpr->w.iJoin==pSubst->iTable + ){ + testcase( ExprHasProperty(pExpr, EP_InnerON) ); + pExpr->w.iJoin = pSubst->iNewTable; + } + if( pExpr->op==TK_COLUMN + && pExpr->iTable==pSubst->iTable + && !ExprHasProperty(pExpr, EP_FixedCol) + ){ +#ifdef SQLITE_ALLOW_ROWID_IN_VIEW + if( pExpr->iColumn<0 ){ + pExpr->op = TK_NULL; + }else +#endif + { + Expr *pNew; + int iColumn; + Expr *pCopy; + Expr ifNullRow; + iColumn = pExpr->iColumn; + assert( iColumn>=0 ); + assert( pSubst->pEList!=0 && iColumn<pSubst->pEList->nExpr ); + assert( pExpr->pRight==0 ); + pCopy = pSubst->pEList->a[iColumn].pExpr; + if( sqlite3ExprIsVector(pCopy) ){ + sqlite3VectorErrorMsg(pSubst->pParse, pCopy); + }else{ + sqlite3 *db = pSubst->pParse->db; + if( pSubst->isOuterJoin + && (pCopy->op!=TK_COLUMN || pCopy->iTable!=pSubst->iNewTable) + ){ + memset(&ifNullRow, 0, sizeof(ifNullRow)); + ifNullRow.op = TK_IF_NULL_ROW; + ifNullRow.pLeft = pCopy; + ifNullRow.iTable = pSubst->iNewTable; + ifNullRow.iColumn = -99; + ifNullRow.flags = EP_IfNullRow; + pCopy = &ifNullRow; + } + testcase( ExprHasProperty(pCopy, EP_Subquery) ); + pNew = sqlite3ExprDup(db, pCopy, 0); + if( db->mallocFailed ){ + sqlite3ExprDelete(db, pNew); + return pExpr; + } + if( pSubst->isOuterJoin ){ + ExprSetProperty(pNew, EP_CanBeNull); + } + if( ExprHasProperty(pExpr,EP_OuterON|EP_InnerON) ){ + sqlite3SetJoinExpr(pNew, pExpr->w.iJoin, + pExpr->flags & (EP_OuterON|EP_InnerON)); + } + sqlite3ExprDelete(db, pExpr); + pExpr = pNew; + if( pExpr->op==TK_TRUEFALSE ){ + pExpr->u.iValue = sqlite3ExprTruthValue(pExpr); + pExpr->op = TK_INTEGER; + ExprSetProperty(pExpr, EP_IntValue); + } + + /* Ensure that the expression now has an implicit collation sequence, + ** just as it did when it was a column of a view or sub-query. */ + { + CollSeq *pNat = sqlite3ExprCollSeq(pSubst->pParse, pExpr); + CollSeq *pColl = sqlite3ExprCollSeq(pSubst->pParse, + pSubst->pCList->a[iColumn].pExpr + ); + if( pNat!=pColl || (pExpr->op!=TK_COLUMN && pExpr->op!=TK_COLLATE) ){ + pExpr = sqlite3ExprAddCollateString(pSubst->pParse, pExpr, + (pColl ? pColl->zName : "BINARY") + ); + } + } + ExprClearProperty(pExpr, EP_Collate); + } + } + }else{ + if( pExpr->op==TK_IF_NULL_ROW && pExpr->iTable==pSubst->iTable ){ + pExpr->iTable = pSubst->iNewTable; + } + pExpr->pLeft = substExpr(pSubst, pExpr->pLeft); + pExpr->pRight = substExpr(pSubst, pExpr->pRight); + if( ExprUseXSelect(pExpr) ){ + substSelect(pSubst, pExpr->x.pSelect, 1); + }else{ + substExprList(pSubst, pExpr->x.pList); + } +#ifndef SQLITE_OMIT_WINDOWFUNC + if( ExprHasProperty(pExpr, EP_WinFunc) ){ + Window *pWin = pExpr->y.pWin; + pWin->pFilter = substExpr(pSubst, pWin->pFilter); + substExprList(pSubst, pWin->pPartition); + substExprList(pSubst, pWin->pOrderBy); + } +#endif + } + return pExpr; +} +static void substExprList( + SubstContext *pSubst, /* Description of the substitution */ + ExprList *pList /* List to scan and in which to make substitutes */ +){ + int i; + if( pList==0 ) return; + for(i=0; i<pList->nExpr; i++){ + pList->a[i].pExpr = substExpr(pSubst, pList->a[i].pExpr); + } +} +static void substSelect( + SubstContext *pSubst, /* Description of the substitution */ + Select *p, /* SELECT statement in which to make substitutions */ + int doPrior /* Do substitutes on p->pPrior too */ +){ + SrcList *pSrc; + SrcItem *pItem; + int i; + if( !p ) return; + do{ + substExprList(pSubst, p->pEList); + substExprList(pSubst, p->pGroupBy); + substExprList(pSubst, p->pOrderBy); + p->pHaving = substExpr(pSubst, p->pHaving); + p->pWhere = substExpr(pSubst, p->pWhere); + pSrc = p->pSrc; + assert( pSrc!=0 ); + for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){ + substSelect(pSubst, pItem->pSelect, 1); + if( pItem->fg.isTabFunc ){ + substExprList(pSubst, pItem->u1.pFuncArg); + } + } + }while( doPrior && (p = p->pPrior)!=0 ); +} +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) +/* +** pSelect is a SELECT statement and pSrcItem is one item in the FROM +** clause of that SELECT. +** +** This routine scans the entire SELECT statement and recomputes the +** pSrcItem->colUsed mask. +*/ +static int recomputeColumnsUsedExpr(Walker *pWalker, Expr *pExpr){ + SrcItem *pItem; + if( pExpr->op!=TK_COLUMN ) return WRC_Continue; + pItem = pWalker->u.pSrcItem; + if( pItem->iCursor!=pExpr->iTable ) return WRC_Continue; + if( pExpr->iColumn<0 ) return WRC_Continue; + pItem->colUsed |= sqlite3ExprColUsed(pExpr); + return WRC_Continue; +} +static void recomputeColumnsUsed( + Select *pSelect, /* The complete SELECT statement */ + SrcItem *pSrcItem /* Which FROM clause item to recompute */ +){ + Walker w; + if( NEVER(pSrcItem->pTab==0) ) return; + memset(&w, 0, sizeof(w)); + w.xExprCallback = recomputeColumnsUsedExpr; + w.xSelectCallback = sqlite3SelectWalkNoop; + w.u.pSrcItem = pSrcItem; + pSrcItem->colUsed = 0; + sqlite3WalkSelect(&w, pSelect); +} +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) +/* +** Assign new cursor numbers to each of the items in pSrc. For each +** new cursor number assigned, set an entry in the aCsrMap[] array +** to map the old cursor number to the new: +** +** aCsrMap[iOld+1] = iNew; +** +** The array is guaranteed by the caller to be large enough for all +** existing cursor numbers in pSrc. aCsrMap[0] is the array size. +** +** If pSrc contains any sub-selects, call this routine recursively +** on the FROM clause of each such sub-select, with iExcept set to -1. +*/ +static void srclistRenumberCursors( + Parse *pParse, /* Parse context */ + int *aCsrMap, /* Array to store cursor mappings in */ + SrcList *pSrc, /* FROM clause to renumber */ + int iExcept /* FROM clause item to skip */ +){ + int i; + SrcItem *pItem; + for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){ + if( i!=iExcept ){ + Select *p; + assert( pItem->iCursor < aCsrMap[0] ); + if( !pItem->fg.isRecursive || aCsrMap[pItem->iCursor+1]==0 ){ + aCsrMap[pItem->iCursor+1] = pParse->nTab++; + } + pItem->iCursor = aCsrMap[pItem->iCursor+1]; + for(p=pItem->pSelect; p; p=p->pPrior){ + srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1); + } + } + } +} + +/* +** *piCursor is a cursor number. Change it if it needs to be mapped. +*/ +static void renumberCursorDoMapping(Walker *pWalker, int *piCursor){ + int *aCsrMap = pWalker->u.aiCol; + int iCsr = *piCursor; + if( iCsr < aCsrMap[0] && aCsrMap[iCsr+1]>0 ){ + *piCursor = aCsrMap[iCsr+1]; + } +} + +/* +** Expression walker callback used by renumberCursors() to update +** Expr objects to match newly assigned cursor numbers. +*/ +static int renumberCursorsCb(Walker *pWalker, Expr *pExpr){ + int op = pExpr->op; + if( op==TK_COLUMN || op==TK_IF_NULL_ROW ){ + renumberCursorDoMapping(pWalker, &pExpr->iTable); + } + if( ExprHasProperty(pExpr, EP_OuterON) ){ + renumberCursorDoMapping(pWalker, &pExpr->w.iJoin); + } + return WRC_Continue; +} + +/* +** Assign a new cursor number to each cursor in the FROM clause (Select.pSrc) +** of the SELECT statement passed as the second argument, and to each +** cursor in the FROM clause of any FROM clause sub-selects, recursively. +** Except, do not assign a new cursor number to the iExcept'th element in +** the FROM clause of (*p). Update all expressions and other references +** to refer to the new cursor numbers. +** +** Argument aCsrMap is an array that may be used for temporary working +** space. Two guarantees are made by the caller: +** +** * the array is larger than the largest cursor number used within the +** select statement passed as an argument, and +** +** * the array entries for all cursor numbers that do *not* appear in +** FROM clauses of the select statement as described above are +** initialized to zero. +*/ +static void renumberCursors( + Parse *pParse, /* Parse context */ + Select *p, /* Select to renumber cursors within */ + int iExcept, /* FROM clause item to skip */ + int *aCsrMap /* Working space */ +){ + Walker w; + srclistRenumberCursors(pParse, aCsrMap, p->pSrc, iExcept); + memset(&w, 0, sizeof(w)); + w.u.aiCol = aCsrMap; + w.xExprCallback = renumberCursorsCb; + w.xSelectCallback = sqlite3SelectWalkNoop; + sqlite3WalkSelect(&w, p); +} +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ + +/* +** If pSel is not part of a compound SELECT, return a pointer to its +** expression list. Otherwise, return a pointer to the expression list +** of the leftmost SELECT in the compound. +*/ +static ExprList *findLeftmostExprlist(Select *pSel){ + while( pSel->pPrior ){ + pSel = pSel->pPrior; + } + return pSel->pEList; +} + +/* +** Return true if any of the result-set columns in the compound query +** have incompatible affinities on one or more arms of the compound. +*/ +static int compoundHasDifferentAffinities(Select *p){ + int ii; + ExprList *pList; + assert( p!=0 ); + assert( p->pEList!=0 ); + assert( p->pPrior!=0 ); + pList = p->pEList; + for(ii=0; ii<pList->nExpr; ii++){ + char aff; + Select *pSub1; + assert( pList->a[ii].pExpr!=0 ); + aff = sqlite3ExprAffinity(pList->a[ii].pExpr); + for(pSub1=p->pPrior; pSub1; pSub1=pSub1->pPrior){ + assert( pSub1->pEList!=0 ); + assert( pSub1->pEList->nExpr>ii ); + assert( pSub1->pEList->a[ii].pExpr!=0 ); + if( sqlite3ExprAffinity(pSub1->pEList->a[ii].pExpr)!=aff ){ + return 1; + } + } + } + return 0; +} + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) +/* +** This routine attempts to flatten subqueries as a performance optimization. +** This routine returns 1 if it makes changes and 0 if no flattening occurs. +** +** To understand the concept of flattening, consider the following +** query: +** +** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5 +** +** The default way of implementing this query is to execute the +** subquery first and store the results in a temporary table, then +** run the outer query on that temporary table. This requires two +** passes over the data. Furthermore, because the temporary table +** has no indices, the WHERE clause on the outer query cannot be +** optimized. +** +** This routine attempts to rewrite queries such as the above into +** a single flat select, like this: +** +** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5 +** +** The code generated for this simplification gives the same result +** but only has to scan the data once. And because indices might +** exist on the table t1, a complete scan of the data might be +** avoided. +** +** Flattening is subject to the following constraints: +** +** (**) We no longer attempt to flatten aggregate subqueries. Was: +** The subquery and the outer query cannot both be aggregates. +** +** (**) We no longer attempt to flatten aggregate subqueries. Was: +** (2) If the subquery is an aggregate then +** (2a) the outer query must not be a join and +** (2b) the outer query must not use subqueries +** other than the one FROM-clause subquery that is a candidate +** for flattening. (This is due to ticket [2f7170d73bf9abf80] +** from 2015-02-09.) +** +** (3) If the subquery is the right operand of a LEFT JOIN then +** (3a) the subquery may not be a join and +** (3b) the FROM clause of the subquery may not contain a virtual +** table and +** (**) Was: "The outer query may not have a GROUP BY." This case +** is now managed correctly +** (3d) the outer query may not be DISTINCT. +** See also (26) for restrictions on RIGHT JOIN. +** +** (4) The subquery can not be DISTINCT. +** +** (**) At one point restrictions (4) and (5) defined a subset of DISTINCT +** sub-queries that were excluded from this optimization. Restriction +** (4) has since been expanded to exclude all DISTINCT subqueries. +** +** (**) We no longer attempt to flatten aggregate subqueries. Was: +** If the subquery is aggregate, the outer query may not be DISTINCT. +** +** (7) The subquery must have a FROM clause. TODO: For subqueries without +** A FROM clause, consider adding a FROM clause with the special +** table sqlite_once that consists of a single row containing a +** single NULL. +** +** (8) If the subquery uses LIMIT then the outer query may not be a join. +** +** (9) If the subquery uses LIMIT then the outer query may not be aggregate. +** +** (**) Restriction (10) was removed from the code on 2005-02-05 but we +** accidentally carried the comment forward until 2014-09-15. Original +** constraint: "If the subquery is aggregate then the outer query +** may not use LIMIT." +** +** (11) The subquery and the outer query may not both have ORDER BY clauses. +** +** (**) Not implemented. Subsumed into restriction (3). Was previously +** a separate restriction deriving from ticket #350. +** +** (13) The subquery and outer query may not both use LIMIT. +** +** (14) The subquery may not use OFFSET. +** +** (15) If the outer query is part of a compound select, then the +** subquery may not use LIMIT. +** (See ticket #2339 and ticket [02a8e81d44]). +** +** (16) If the outer query is aggregate, then the subquery may not +** use ORDER BY. (Ticket #2942) This used to not matter +** until we introduced the group_concat() function. +** +** (17) If the subquery is a compound select, then +** (17a) all compound operators must be a UNION ALL, and +** (17b) no terms within the subquery compound may be aggregate +** or DISTINCT, and +** (17c) every term within the subquery compound must have a FROM clause +** (17d) the outer query may not be +** (17d1) aggregate, or +** (17d2) DISTINCT +** (17e) the subquery may not contain window functions, and +** (17f) the subquery must not be the RHS of a LEFT JOIN. +** (17g) either the subquery is the first element of the outer +** query or there are no RIGHT or FULL JOINs in any arm +** of the subquery. (This is a duplicate of condition (27b).) +** (17h) The corresponding result set expressions in all arms of the +** compound must have the same affinity. +** +** The parent and sub-query may contain WHERE clauses. Subject to +** rules (11), (13) and (14), they may also contain ORDER BY, +** LIMIT and OFFSET clauses. The subquery cannot use any compound +** operator other than UNION ALL because all the other compound +** operators have an implied DISTINCT which is disallowed by +** restriction (4). +** +** Also, each component of the sub-query must return the same number +** of result columns. This is actually a requirement for any compound +** SELECT statement, but all the code here does is make sure that no +** such (illegal) sub-query is flattened. The caller will detect the +** syntax error and return a detailed message. +** +** (18) If the sub-query is a compound select, then all terms of the +** ORDER BY clause of the parent must be copies of a term returned +** by the parent query. +** +** (19) If the subquery uses LIMIT then the outer query may not +** have a WHERE clause. +** +** (20) If the sub-query is a compound select, then it must not use +** an ORDER BY clause. Ticket #3773. We could relax this constraint +** somewhat by saying that the terms of the ORDER BY clause must +** appear as unmodified result columns in the outer query. But we +** have other optimizations in mind to deal with that case. +** +** (21) If the subquery uses LIMIT then the outer query may not be +** DISTINCT. (See ticket [752e1646fc]). +** +** (22) The subquery may not be a recursive CTE. +** +** (23) If the outer query is a recursive CTE, then the sub-query may not be +** a compound query. This restriction is because transforming the +** parent to a compound query confuses the code that handles +** recursive queries in multiSelect(). +** +** (**) We no longer attempt to flatten aggregate subqueries. Was: +** The subquery may not be an aggregate that uses the built-in min() or +** or max() functions. (Without this restriction, a query like: +** "SELECT x FROM (SELECT max(y), x FROM t1)" would not necessarily +** return the value X for which Y was maximal.) +** +** (25) If either the subquery or the parent query contains a window +** function in the select list or ORDER BY clause, flattening +** is not attempted. +** +** (26) The subquery may not be the right operand of a RIGHT JOIN. +** See also (3) for restrictions on LEFT JOIN. +** +** (27) The subquery may not contain a FULL or RIGHT JOIN unless it +** is the first element of the parent query. Two subcases: +** (27a) the subquery is not a compound query. +** (27b) the subquery is a compound query and the RIGHT JOIN occurs +** in any arm of the compound query. (See also (17g).) +** +** (28) The subquery is not a MATERIALIZED CTE. (This is handled +** in the caller before ever reaching this routine.) +** +** +** In this routine, the "p" parameter is a pointer to the outer query. +** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query +** uses aggregates. +** +** If flattening is not attempted, this routine is a no-op and returns 0. +** If flattening is attempted this routine returns 1. +** +** All of the expression analysis must occur on both the outer query and +** the subquery before this routine runs. +*/ +static int flattenSubquery( + Parse *pParse, /* Parsing context */ + Select *p, /* The parent or outer SELECT statement */ + int iFrom, /* Index in p->pSrc->a[] of the inner subquery */ + int isAgg /* True if outer SELECT uses aggregate functions */ +){ + const char *zSavedAuthContext = pParse->zAuthContext; + Select *pParent; /* Current UNION ALL term of the other query */ + Select *pSub; /* The inner query or "subquery" */ + Select *pSub1; /* Pointer to the rightmost select in sub-query */ + SrcList *pSrc; /* The FROM clause of the outer query */ + SrcList *pSubSrc; /* The FROM clause of the subquery */ + int iParent; /* VDBE cursor number of the pSub result set temp table */ + int iNewParent = -1;/* Replacement table for iParent */ + int isOuterJoin = 0; /* True if pSub is the right side of a LEFT JOIN */ + int i; /* Loop counter */ + Expr *pWhere; /* The WHERE clause */ + SrcItem *pSubitem; /* The subquery */ + sqlite3 *db = pParse->db; + Walker w; /* Walker to persist agginfo data */ + int *aCsrMap = 0; + + /* Check to see if flattening is permitted. Return 0 if not. + */ + assert( p!=0 ); + assert( p->pPrior==0 ); + if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0; + pSrc = p->pSrc; + assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc ); + pSubitem = &pSrc->a[iFrom]; + iParent = pSubitem->iCursor; + pSub = pSubitem->pSelect; + assert( pSub!=0 ); + +#ifndef SQLITE_OMIT_WINDOWFUNC + if( p->pWin || pSub->pWin ) return 0; /* Restriction (25) */ +#endif + + pSubSrc = pSub->pSrc; + assert( pSubSrc ); + /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants, + ** not arbitrary expressions, we allowed some combining of LIMIT and OFFSET + ** because they could be computed at compile-time. But when LIMIT and OFFSET + ** became arbitrary expressions, we were forced to add restrictions (13) + ** and (14). */ + if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */ + if( pSub->pLimit && pSub->pLimit->pRight ) return 0; /* Restriction (14) */ + if( (p->selFlags & SF_Compound)!=0 && pSub->pLimit ){ + return 0; /* Restriction (15) */ + } + if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */ + if( pSub->selFlags & SF_Distinct ) return 0; /* Restriction (4) */ + if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){ + return 0; /* Restrictions (8)(9) */ + } + if( p->pOrderBy && pSub->pOrderBy ){ + return 0; /* Restriction (11) */ + } + if( isAgg && pSub->pOrderBy ) return 0; /* Restriction (16) */ + if( pSub->pLimit && p->pWhere ) return 0; /* Restriction (19) */ + if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){ + return 0; /* Restriction (21) */ + } + if( pSub->selFlags & (SF_Recursive) ){ + return 0; /* Restrictions (22) */ + } + + /* + ** If the subquery is the right operand of a LEFT JOIN, then the + ** subquery may not be a join itself (3a). Example of why this is not + ** allowed: + ** + ** t1 LEFT OUTER JOIN (t2 JOIN t3) + ** + ** If we flatten the above, we would get + ** + ** (t1 LEFT OUTER JOIN t2) JOIN t3 + ** + ** which is not at all the same thing. + ** + ** See also tickets #306, #350, and #3300. + */ + if( (pSubitem->fg.jointype & (JT_OUTER|JT_LTORJ))!=0 ){ + if( pSubSrc->nSrc>1 /* (3a) */ + || IsVirtual(pSubSrc->a[0].pTab) /* (3b) */ + || (p->selFlags & SF_Distinct)!=0 /* (3d) */ + || (pSubitem->fg.jointype & JT_RIGHT)!=0 /* (26) */ + ){ + return 0; + } + isOuterJoin = 1; + } + + assert( pSubSrc->nSrc>0 ); /* True by restriction (7) */ + if( iFrom>0 && (pSubSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){ + return 0; /* Restriction (27a) */ + } + + /* Condition (28) is blocked by the caller */ + assert( !pSubitem->fg.isCte || pSubitem->u2.pCteUse->eM10d!=M10d_Yes ); + + /* Restriction (17): If the sub-query is a compound SELECT, then it must + ** use only the UNION ALL operator. And none of the simple select queries + ** that make up the compound SELECT are allowed to be aggregate or distinct + ** queries. + */ + if( pSub->pPrior ){ + int ii; + if( pSub->pOrderBy ){ + return 0; /* Restriction (20) */ + } + if( isAgg || (p->selFlags & SF_Distinct)!=0 || isOuterJoin>0 ){ + return 0; /* (17d1), (17d2), or (17f) */ + } + for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){ + testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct ); + testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate ); + assert( pSub->pSrc!=0 ); + assert( (pSub->selFlags & SF_Recursive)==0 ); + assert( pSub->pEList->nExpr==pSub1->pEList->nExpr ); + if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0 /* (17b) */ + || (pSub1->pPrior && pSub1->op!=TK_ALL) /* (17a) */ + || pSub1->pSrc->nSrc<1 /* (17c) */ +#ifndef SQLITE_OMIT_WINDOWFUNC + || pSub1->pWin /* (17e) */ +#endif + ){ + return 0; + } + if( iFrom>0 && (pSub1->pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){ + /* Without this restriction, the JT_LTORJ flag would end up being + ** omitted on left-hand tables of the right join that is being + ** flattened. */ + return 0; /* Restrictions (17g), (27b) */ + } + testcase( pSub1->pSrc->nSrc>1 ); + } + + /* Restriction (18). */ + if( p->pOrderBy ){ + for(ii=0; ii<p->pOrderBy->nExpr; ii++){ + if( p->pOrderBy->a[ii].u.x.iOrderByCol==0 ) return 0; + } + } + + /* Restriction (23) */ + if( (p->selFlags & SF_Recursive) ) return 0; + + /* Restriction (17h) */ + if( compoundHasDifferentAffinities(pSub) ) return 0; + + if( pSrc->nSrc>1 ){ + if( pParse->nSelect>500 ) return 0; + if( OptimizationDisabled(db, SQLITE_FlttnUnionAll) ) return 0; + aCsrMap = sqlite3DbMallocZero(db, ((i64)pParse->nTab+1)*sizeof(int)); + if( aCsrMap ) aCsrMap[0] = pParse->nTab; + } + } + + /***** If we reach this point, flattening is permitted. *****/ + TREETRACE(0x4,pParse,p,("flatten %u.%p from term %d\n", + pSub->selId, pSub, iFrom)); + + /* Authorize the subquery */ + pParse->zAuthContext = pSubitem->zName; + TESTONLY(i =) sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0); + testcase( i==SQLITE_DENY ); + pParse->zAuthContext = zSavedAuthContext; + + /* Delete the transient structures associated with the subquery */ + pSub1 = pSubitem->pSelect; + sqlite3DbFree(db, pSubitem->zDatabase); + sqlite3DbFree(db, pSubitem->zName); + sqlite3DbFree(db, pSubitem->zAlias); + pSubitem->zDatabase = 0; + pSubitem->zName = 0; + pSubitem->zAlias = 0; + pSubitem->pSelect = 0; + assert( pSubitem->fg.isUsing!=0 || pSubitem->u3.pOn==0 ); + + /* If the sub-query is a compound SELECT statement, then (by restrictions + ** 17 and 18 above) it must be a UNION ALL and the parent query must + ** be of the form: + ** + ** SELECT <expr-list> FROM (<sub-query>) <where-clause> + ** + ** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block + ** creates N-1 copies of the parent query without any ORDER BY, LIMIT or + ** OFFSET clauses and joins them to the left-hand-side of the original + ** using UNION ALL operators. In this case N is the number of simple + ** select statements in the compound sub-query. + ** + ** Example: + ** + ** SELECT a+1 FROM ( + ** SELECT x FROM tab + ** UNION ALL + ** SELECT y FROM tab + ** UNION ALL + ** SELECT abs(z*2) FROM tab2 + ** ) WHERE a!=5 ORDER BY 1 + ** + ** Transformed into: + ** + ** SELECT x+1 FROM tab WHERE x+1!=5 + ** UNION ALL + ** SELECT y+1 FROM tab WHERE y+1!=5 + ** UNION ALL + ** SELECT abs(z*2)+1 FROM tab2 WHERE abs(z*2)+1!=5 + ** ORDER BY 1 + ** + ** We call this the "compound-subquery flattening". + */ + for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){ + Select *pNew; + ExprList *pOrderBy = p->pOrderBy; + Expr *pLimit = p->pLimit; + Select *pPrior = p->pPrior; + Table *pItemTab = pSubitem->pTab; + pSubitem->pTab = 0; + p->pOrderBy = 0; + p->pPrior = 0; + p->pLimit = 0; + pNew = sqlite3SelectDup(db, p, 0); + p->pLimit = pLimit; + p->pOrderBy = pOrderBy; + p->op = TK_ALL; + pSubitem->pTab = pItemTab; + if( pNew==0 ){ + p->pPrior = pPrior; + }else{ + pNew->selId = ++pParse->nSelect; + if( aCsrMap && ALWAYS(db->mallocFailed==0) ){ + renumberCursors(pParse, pNew, iFrom, aCsrMap); + } + pNew->pPrior = pPrior; + if( pPrior ) pPrior->pNext = pNew; + pNew->pNext = p; + p->pPrior = pNew; + TREETRACE(0x4,pParse,p,("compound-subquery flattener" + " creates %u as peer\n",pNew->selId)); + } + assert( pSubitem->pSelect==0 ); + } + sqlite3DbFree(db, aCsrMap); + if( db->mallocFailed ){ + pSubitem->pSelect = pSub1; + return 1; + } + + /* Defer deleting the Table object associated with the + ** subquery until code generation is + ** complete, since there may still exist Expr.pTab entries that + ** refer to the subquery even after flattening. Ticket #3346. + ** + ** pSubitem->pTab is always non-NULL by test restrictions and tests above. + */ + if( ALWAYS(pSubitem->pTab!=0) ){ + Table *pTabToDel = pSubitem->pTab; + if( pTabToDel->nTabRef==1 ){ + Parse *pToplevel = sqlite3ParseToplevel(pParse); + sqlite3ParserAddCleanup(pToplevel, sqlite3DeleteTableGeneric, pTabToDel); + testcase( pToplevel->earlyCleanup ); + }else{ + pTabToDel->nTabRef--; + } + pSubitem->pTab = 0; + } + + /* The following loop runs once for each term in a compound-subquery + ** flattening (as described above). If we are doing a different kind + ** of flattening - a flattening other than a compound-subquery flattening - + ** then this loop only runs once. + ** + ** This loop moves all of the FROM elements of the subquery into the + ** the FROM clause of the outer query. Before doing this, remember + ** the cursor number for the original outer query FROM element in + ** iParent. The iParent cursor will never be used. Subsequent code + ** will scan expressions looking for iParent references and replace + ** those references with expressions that resolve to the subquery FROM + ** elements we are now copying in. + */ + pSub = pSub1; + for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){ + int nSubSrc; + u8 jointype = 0; + u8 ltorj = pSrc->a[iFrom].fg.jointype & JT_LTORJ; + assert( pSub!=0 ); + pSubSrc = pSub->pSrc; /* FROM clause of subquery */ + nSubSrc = pSubSrc->nSrc; /* Number of terms in subquery FROM clause */ + pSrc = pParent->pSrc; /* FROM clause of the outer query */ + + if( pParent==p ){ + jointype = pSubitem->fg.jointype; /* First time through the loop */ + } + + /* The subquery uses a single slot of the FROM clause of the outer + ** query. If the subquery has more than one element in its FROM clause, + ** then expand the outer query to make space for it to hold all elements + ** of the subquery. + ** + ** Example: + ** + ** SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB; + ** + ** The outer query has 3 slots in its FROM clause. One slot of the + ** outer query (the middle slot) is used by the subquery. The next + ** block of code will expand the outer query FROM clause to 4 slots. + ** The middle slot is expanded to two slots in order to make space + ** for the two elements in the FROM clause of the subquery. + */ + if( nSubSrc>1 ){ + pSrc = sqlite3SrcListEnlarge(pParse, pSrc, nSubSrc-1,iFrom+1); + if( pSrc==0 ) break; + pParent->pSrc = pSrc; + } + + /* Transfer the FROM clause terms from the subquery into the + ** outer query. + */ + for(i=0; i<nSubSrc; i++){ + SrcItem *pItem = &pSrc->a[i+iFrom]; + if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing); + assert( pItem->fg.isTabFunc==0 ); + *pItem = pSubSrc->a[i]; + pItem->fg.jointype |= ltorj; + iNewParent = pSubSrc->a[i].iCursor; + memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i])); + } + pSrc->a[iFrom].fg.jointype &= JT_LTORJ; + pSrc->a[iFrom].fg.jointype |= jointype | ltorj; + + /* Now begin substituting subquery result set expressions for + ** references to the iParent in the outer query. + ** + ** Example: + ** + ** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b; + ** \ \_____________ subquery __________/ / + ** \_____________________ outer query ______________________________/ + ** + ** We look at every expression in the outer query and every place we see + ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10". + */ + if( pSub->pOrderBy && (pParent->selFlags & SF_NoopOrderBy)==0 ){ + /* At this point, any non-zero iOrderByCol values indicate that the + ** ORDER BY column expression is identical to the iOrderByCol'th + ** expression returned by SELECT statement pSub. Since these values + ** do not necessarily correspond to columns in SELECT statement pParent, + ** zero them before transferring the ORDER BY clause. + ** + ** Not doing this may cause an error if a subsequent call to this + ** function attempts to flatten a compound sub-query into pParent + ** (the only way this can happen is if the compound sub-query is + ** currently part of pSub->pSrc). See ticket [d11a6e908f]. */ + ExprList *pOrderBy = pSub->pOrderBy; + for(i=0; i<pOrderBy->nExpr; i++){ + pOrderBy->a[i].u.x.iOrderByCol = 0; + } + assert( pParent->pOrderBy==0 ); + pParent->pOrderBy = pOrderBy; + pSub->pOrderBy = 0; + } + pWhere = pSub->pWhere; + pSub->pWhere = 0; + if( isOuterJoin>0 ){ + sqlite3SetJoinExpr(pWhere, iNewParent, EP_OuterON); + } + if( pWhere ){ + if( pParent->pWhere ){ + pParent->pWhere = sqlite3PExpr(pParse, TK_AND, pWhere, pParent->pWhere); + }else{ + pParent->pWhere = pWhere; + } + } + if( db->mallocFailed==0 ){ + SubstContext x; + x.pParse = pParse; + x.iTable = iParent; + x.iNewTable = iNewParent; + x.isOuterJoin = isOuterJoin; + x.pEList = pSub->pEList; + x.pCList = findLeftmostExprlist(pSub); + substSelect(&x, pParent, 0); + } + + /* The flattened query is a compound if either the inner or the + ** outer query is a compound. */ + pParent->selFlags |= pSub->selFlags & SF_Compound; + assert( (pSub->selFlags & SF_Distinct)==0 ); /* restriction (17b) */ + + /* + ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y; + ** + ** One is tempted to try to add a and b to combine the limits. But this + ** does not work if either limit is negative. + */ + if( pSub->pLimit ){ + pParent->pLimit = pSub->pLimit; + pSub->pLimit = 0; + } + + /* Recompute the SrcItem.colUsed masks for the flattened + ** tables. */ + for(i=0; i<nSubSrc; i++){ + recomputeColumnsUsed(pParent, &pSrc->a[i+iFrom]); + } + } + + /* Finally, delete what is left of the subquery and return success. + */ + sqlite3AggInfoPersistWalkerInit(&w, pParse); + sqlite3WalkSelect(&w,pSub1); + sqlite3SelectDelete(db, pSub1); + +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x4 ){ + TREETRACE(0x4,pParse,p,("After flattening:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + + return 1; +} +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ + +/* +** A structure to keep track of all of the column values that are fixed to +** a known value due to WHERE clause constraints of the form COLUMN=VALUE. +*/ +typedef struct WhereConst WhereConst; +struct WhereConst { + Parse *pParse; /* Parsing context */ + u8 *pOomFault; /* Pointer to pParse->db->mallocFailed */ + int nConst; /* Number for COLUMN=CONSTANT terms */ + int nChng; /* Number of times a constant is propagated */ + int bHasAffBlob; /* At least one column in apExpr[] as affinity BLOB */ + u32 mExcludeOn; /* Which ON expressions to exclude from considertion. + ** Either EP_OuterON or EP_InnerON|EP_OuterON */ + Expr **apExpr; /* [i*2] is COLUMN and [i*2+1] is VALUE */ +}; + +/* +** Add a new entry to the pConst object. Except, do not add duplicate +** pColumn entries. Also, do not add if doing so would not be appropriate. +** +** The caller guarantees the pColumn is a column and pValue is a constant. +** This routine has to do some additional checks before completing the +** insert. +*/ +static void constInsert( + WhereConst *pConst, /* The WhereConst into which we are inserting */ + Expr *pColumn, /* The COLUMN part of the constraint */ + Expr *pValue, /* The VALUE part of the constraint */ + Expr *pExpr /* Overall expression: COLUMN=VALUE or VALUE=COLUMN */ +){ + int i; + assert( pColumn->op==TK_COLUMN ); + assert( sqlite3ExprIsConstant(pValue) ); + + if( ExprHasProperty(pColumn, EP_FixedCol) ) return; + if( sqlite3ExprAffinity(pValue)!=0 ) return; + if( !sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr)) ){ + return; + } + + /* 2018-10-25 ticket [cf5ed20f] + ** Make sure the same pColumn is not inserted more than once */ + for(i=0; i<pConst->nConst; i++){ + const Expr *pE2 = pConst->apExpr[i*2]; + assert( pE2->op==TK_COLUMN ); + if( pE2->iTable==pColumn->iTable + && pE2->iColumn==pColumn->iColumn + ){ + return; /* Already present. Return without doing anything. */ + } + } + if( sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){ + pConst->bHasAffBlob = 1; + } + + pConst->nConst++; + pConst->apExpr = sqlite3DbReallocOrFree(pConst->pParse->db, pConst->apExpr, + pConst->nConst*2*sizeof(Expr*)); + if( pConst->apExpr==0 ){ + pConst->nConst = 0; + }else{ + pConst->apExpr[pConst->nConst*2-2] = pColumn; + pConst->apExpr[pConst->nConst*2-1] = pValue; + } +} + +/* +** Find all terms of COLUMN=VALUE or VALUE=COLUMN in pExpr where VALUE +** is a constant expression and where the term must be true because it +** is part of the AND-connected terms of the expression. For each term +** found, add it to the pConst structure. +*/ +static void findConstInWhere(WhereConst *pConst, Expr *pExpr){ + Expr *pRight, *pLeft; + if( NEVER(pExpr==0) ) return; + if( ExprHasProperty(pExpr, pConst->mExcludeOn) ){ + testcase( ExprHasProperty(pExpr, EP_OuterON) ); + testcase( ExprHasProperty(pExpr, EP_InnerON) ); + return; + } + if( pExpr->op==TK_AND ){ + findConstInWhere(pConst, pExpr->pRight); + findConstInWhere(pConst, pExpr->pLeft); + return; + } + if( pExpr->op!=TK_EQ ) return; + pRight = pExpr->pRight; + pLeft = pExpr->pLeft; + assert( pRight!=0 ); + assert( pLeft!=0 ); + if( pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pLeft) ){ + constInsert(pConst,pRight,pLeft,pExpr); + } + if( pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pRight) ){ + constInsert(pConst,pLeft,pRight,pExpr); + } +} + +/* +** This is a helper function for Walker callback propagateConstantExprRewrite(). +** +** Argument pExpr is a candidate expression to be replaced by a value. If +** pExpr is equivalent to one of the columns named in pWalker->u.pConst, +** then overwrite it with the corresponding value. Except, do not do so +** if argument bIgnoreAffBlob is non-zero and the affinity of pExpr +** is SQLITE_AFF_BLOB. +*/ +static int propagateConstantExprRewriteOne( + WhereConst *pConst, + Expr *pExpr, + int bIgnoreAffBlob +){ + int i; + if( pConst->pOomFault[0] ) return WRC_Prune; + if( pExpr->op!=TK_COLUMN ) return WRC_Continue; + if( ExprHasProperty(pExpr, EP_FixedCol|pConst->mExcludeOn) ){ + testcase( ExprHasProperty(pExpr, EP_FixedCol) ); + testcase( ExprHasProperty(pExpr, EP_OuterON) ); + testcase( ExprHasProperty(pExpr, EP_InnerON) ); + return WRC_Continue; + } + for(i=0; i<pConst->nConst; i++){ + Expr *pColumn = pConst->apExpr[i*2]; + if( pColumn==pExpr ) continue; + if( pColumn->iTable!=pExpr->iTable ) continue; + if( pColumn->iColumn!=pExpr->iColumn ) continue; + if( bIgnoreAffBlob && sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){ + break; + } + /* A match is found. Add the EP_FixedCol property */ + pConst->nChng++; + ExprClearProperty(pExpr, EP_Leaf); + ExprSetProperty(pExpr, EP_FixedCol); + assert( pExpr->pLeft==0 ); + pExpr->pLeft = sqlite3ExprDup(pConst->pParse->db, pConst->apExpr[i*2+1], 0); + if( pConst->pParse->db->mallocFailed ) return WRC_Prune; + break; + } + return WRC_Prune; +} + +/* +** This is a Walker expression callback. pExpr is a node from the WHERE +** clause of a SELECT statement. This function examines pExpr to see if +** any substitutions based on the contents of pWalker->u.pConst should +** be made to pExpr or its immediate children. +** +** A substitution is made if: +** +** + pExpr is a column with an affinity other than BLOB that matches +** one of the columns in pWalker->u.pConst, or +** +** + pExpr is a binary comparison operator (=, <=, >=, <, >) that +** uses an affinity other than TEXT and one of its immediate +** children is a column that matches one of the columns in +** pWalker->u.pConst. +*/ +static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){ + WhereConst *pConst = pWalker->u.pConst; + assert( TK_GT==TK_EQ+1 ); + assert( TK_LE==TK_EQ+2 ); + assert( TK_LT==TK_EQ+3 ); + assert( TK_GE==TK_EQ+4 ); + if( pConst->bHasAffBlob ){ + if( (pExpr->op>=TK_EQ && pExpr->op<=TK_GE) + || pExpr->op==TK_IS + ){ + propagateConstantExprRewriteOne(pConst, pExpr->pLeft, 0); + if( pConst->pOomFault[0] ) return WRC_Prune; + if( sqlite3ExprAffinity(pExpr->pLeft)!=SQLITE_AFF_TEXT ){ + propagateConstantExprRewriteOne(pConst, pExpr->pRight, 0); + } + } + } + return propagateConstantExprRewriteOne(pConst, pExpr, pConst->bHasAffBlob); +} + +/* +** The WHERE-clause constant propagation optimization. +** +** If the WHERE clause contains terms of the form COLUMN=CONSTANT or +** CONSTANT=COLUMN that are top-level AND-connected terms that are not +** part of a ON clause from a LEFT JOIN, then throughout the query +** replace all other occurrences of COLUMN with CONSTANT. +** +** For example, the query: +** +** SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=t1.a AND t3.c=t2.b +** +** Is transformed into +** +** SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=39 AND t3.c=39 +** +** Return true if any transformations where made and false if not. +** +** Implementation note: Constant propagation is tricky due to affinity +** and collating sequence interactions. Consider this example: +** +** CREATE TABLE t1(a INT,b TEXT); +** INSERT INTO t1 VALUES(123,'0123'); +** SELECT * FROM t1 WHERE a=123 AND b=a; +** SELECT * FROM t1 WHERE a=123 AND b=123; +** +** The two SELECT statements above should return different answers. b=a +** is always true because the comparison uses numeric affinity, but b=123 +** is false because it uses text affinity and '0123' is not the same as '123'. +** To work around this, the expression tree is not actually changed from +** "b=a" to "b=123" but rather the "a" in "b=a" is tagged with EP_FixedCol +** and the "123" value is hung off of the pLeft pointer. Code generator +** routines know to generate the constant "123" instead of looking up the +** column value. Also, to avoid collation problems, this optimization is +** only attempted if the "a=123" term uses the default BINARY collation. +** +** 2021-05-25 forum post 6a06202608: Another troublesome case is... +** +** CREATE TABLE t1(x); +** INSERT INTO t1 VALUES(10.0); +** SELECT 1 FROM t1 WHERE x=10 AND x LIKE 10; +** +** The query should return no rows, because the t1.x value is '10.0' not '10' +** and '10.0' is not LIKE '10'. But if we are not careful, the first WHERE +** term "x=10" will cause the second WHERE term to become "10 LIKE 10", +** resulting in a false positive. To avoid this, constant propagation for +** columns with BLOB affinity is only allowed if the constant is used with +** operators ==, <=, <, >=, >, or IS in a way that will cause the correct +** type conversions to occur. See logic associated with the bHasAffBlob flag +** for details. +*/ +static int propagateConstants( + Parse *pParse, /* The parsing context */ + Select *p /* The query in which to propagate constants */ +){ + WhereConst x; + Walker w; + int nChng = 0; + x.pParse = pParse; + x.pOomFault = &pParse->db->mallocFailed; + do{ + x.nConst = 0; + x.nChng = 0; + x.apExpr = 0; + x.bHasAffBlob = 0; + if( ALWAYS(p->pSrc!=0) + && p->pSrc->nSrc>0 + && (p->pSrc->a[0].fg.jointype & JT_LTORJ)!=0 + ){ + /* Do not propagate constants on any ON clause if there is a + ** RIGHT JOIN anywhere in the query */ + x.mExcludeOn = EP_InnerON | EP_OuterON; + }else{ + /* Do not propagate constants through the ON clause of a LEFT JOIN */ + x.mExcludeOn = EP_OuterON; + } + findConstInWhere(&x, p->pWhere); + if( x.nConst ){ + memset(&w, 0, sizeof(w)); + w.pParse = pParse; + w.xExprCallback = propagateConstantExprRewrite; + w.xSelectCallback = sqlite3SelectWalkNoop; + w.xSelectCallback2 = 0; + w.walkerDepth = 0; + w.u.pConst = &x; + sqlite3WalkExpr(&w, p->pWhere); + sqlite3DbFree(x.pParse->db, x.apExpr); + nChng += x.nChng; + } + }while( x.nChng ); + return nChng; +} + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) +# if !defined(SQLITE_OMIT_WINDOWFUNC) +/* +** This function is called to determine whether or not it is safe to +** push WHERE clause expression pExpr down to FROM clause sub-query +** pSubq, which contains at least one window function. Return 1 +** if it is safe and the expression should be pushed down, or 0 +** otherwise. +** +** It is only safe to push the expression down if it consists only +** of constants and copies of expressions that appear in the PARTITION +** BY clause of all window function used by the sub-query. It is safe +** to filter out entire partitions, but not rows within partitions, as +** this may change the results of the window functions. +** +** At the time this function is called it is guaranteed that +** +** * the sub-query uses only one distinct window frame, and +** * that the window frame has a PARTITION BY clause. +*/ +static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){ + assert( pSubq->pWin->pPartition ); + assert( (pSubq->selFlags & SF_MultiPart)==0 ); + assert( pSubq->pPrior==0 ); + return sqlite3ExprIsConstantOrGroupBy(pParse, pExpr, pSubq->pWin->pPartition); +} +# endif /* SQLITE_OMIT_WINDOWFUNC */ +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) +/* +** Make copies of relevant WHERE clause terms of the outer query into +** the WHERE clause of subquery. Example: +** +** SELECT * FROM (SELECT a AS x, c-d AS y FROM t1) WHERE x=5 AND y=10; +** +** Transformed into: +** +** SELECT * FROM (SELECT a AS x, c-d AS y FROM t1 WHERE a=5 AND c-d=10) +** WHERE x=5 AND y=10; +** +** The hope is that the terms added to the inner query will make it more +** efficient. +** +** Do not attempt this optimization if: +** +** (1) (** This restriction was removed on 2017-09-29. We used to +** disallow this optimization for aggregate subqueries, but now +** it is allowed by putting the extra terms on the HAVING clause. +** The added HAVING clause is pointless if the subquery lacks +** a GROUP BY clause. But such a HAVING clause is also harmless +** so there does not appear to be any reason to add extra logic +** to suppress it. **) +** +** (2) The inner query is the recursive part of a common table expression. +** +** (3) The inner query has a LIMIT clause (since the changes to the WHERE +** clause would change the meaning of the LIMIT). +** +** (4) The inner query is the right operand of a LEFT JOIN and the +** expression to be pushed down does not come from the ON clause +** on that LEFT JOIN. +** +** (5) The WHERE clause expression originates in the ON or USING clause +** of a LEFT JOIN where iCursor is not the right-hand table of that +** left join. An example: +** +** SELECT * +** FROM (SELECT 1 AS a1 UNION ALL SELECT 2) AS aa +** JOIN (SELECT 1 AS b2 UNION ALL SELECT 2) AS bb ON (a1=b2) +** LEFT JOIN (SELECT 8 AS c3 UNION ALL SELECT 9) AS cc ON (b2=2); +** +** The correct answer is three rows: (1,1,NULL),(2,2,8),(2,2,9). +** But if the (b2=2) term were to be pushed down into the bb subquery, +** then the (1,1,NULL) row would be suppressed. +** +** (6) Window functions make things tricky as changes to the WHERE clause +** of the inner query could change the window over which window +** functions are calculated. Therefore, do not attempt the optimization +** if: +** +** (6a) The inner query uses multiple incompatible window partitions. +** +** (6b) The inner query is a compound and uses window-functions. +** +** (6c) The WHERE clause does not consist entirely of constants and +** copies of expressions found in the PARTITION BY clause of +** all window-functions used by the sub-query. It is safe to +** filter out entire partitions, as this does not change the +** window over which any window-function is calculated. +** +** (7) The inner query is a Common Table Expression (CTE) that should +** be materialized. (This restriction is implemented in the calling +** routine.) +** +** (8) If the subquery is a compound that uses UNION, INTERSECT, +** or EXCEPT, then all of the result set columns for all arms of +** the compound must use the BINARY collating sequence. +** +** (9) All three of the following are true: +** +** (9a) The WHERE clause expression originates in the ON or USING clause +** of a join (either an INNER or an OUTER join), and +** +** (9b) The subquery is to the right of the ON/USING clause +** +** (9c) There is a RIGHT JOIN (or FULL JOIN) in between the ON/USING +** clause and the subquery. +** +** Without this restriction, the push-down optimization might move +** the ON/USING filter expression from the left side of a RIGHT JOIN +** over to the right side, which leads to incorrect answers. See +** also restriction (6) in sqlite3ExprIsSingleTableConstraint(). +** +** (10) The inner query is not the right-hand table of a RIGHT JOIN. +** +** (11) The subquery is not a VALUES clause +** +** Return 0 if no changes are made and non-zero if one or more WHERE clause +** terms are duplicated into the subquery. +*/ +static int pushDownWhereTerms( + Parse *pParse, /* Parse context (for malloc() and error reporting) */ + Select *pSubq, /* The subquery whose WHERE clause is to be augmented */ + Expr *pWhere, /* The WHERE clause of the outer query */ + SrcList *pSrcList, /* The complete from clause of the outer query */ + int iSrc /* Which FROM clause term to try to push into */ +){ + Expr *pNew; + SrcItem *pSrc; /* The subquery FROM term into which WHERE is pushed */ + int nChng = 0; + pSrc = &pSrcList->a[iSrc]; + if( pWhere==0 ) return 0; + if( pSubq->selFlags & (SF_Recursive|SF_MultiPart) ){ + return 0; /* restrictions (2) and (11) */ + } + if( pSrc->fg.jointype & (JT_LTORJ|JT_RIGHT) ){ + return 0; /* restrictions (10) */ + } + + if( pSubq->pPrior ){ + Select *pSel; + int notUnionAll = 0; + for(pSel=pSubq; pSel; pSel=pSel->pPrior){ + u8 op = pSel->op; + assert( op==TK_ALL || op==TK_SELECT + || op==TK_UNION || op==TK_INTERSECT || op==TK_EXCEPT ); + if( op!=TK_ALL && op!=TK_SELECT ){ + notUnionAll = 1; + } +#ifndef SQLITE_OMIT_WINDOWFUNC + if( pSel->pWin ) return 0; /* restriction (6b) */ +#endif + } + if( notUnionAll ){ + /* If any of the compound arms are connected using UNION, INTERSECT, + ** or EXCEPT, then we must ensure that none of the columns use a + ** non-BINARY collating sequence. */ + for(pSel=pSubq; pSel; pSel=pSel->pPrior){ + int ii; + const ExprList *pList = pSel->pEList; + assert( pList!=0 ); + for(ii=0; ii<pList->nExpr; ii++){ + CollSeq *pColl = sqlite3ExprCollSeq(pParse, pList->a[ii].pExpr); + if( !sqlite3IsBinary(pColl) ){ + return 0; /* Restriction (8) */ + } + } + } + } + }else{ +#ifndef SQLITE_OMIT_WINDOWFUNC + if( pSubq->pWin && pSubq->pWin->pPartition==0 ) return 0; +#endif + } + +#ifdef SQLITE_DEBUG + /* Only the first term of a compound can have a WITH clause. But make + ** sure no other terms are marked SF_Recursive in case something changes + ** in the future. + */ + { + Select *pX; + for(pX=pSubq; pX; pX=pX->pPrior){ + assert( (pX->selFlags & (SF_Recursive))==0 ); + } + } +#endif + + if( pSubq->pLimit!=0 ){ + return 0; /* restriction (3) */ + } + while( pWhere->op==TK_AND ){ + nChng += pushDownWhereTerms(pParse, pSubq, pWhere->pRight, pSrcList, iSrc); + pWhere = pWhere->pLeft; + } + +#if 0 /* These checks now done by sqlite3ExprIsSingleTableConstraint() */ + if( ExprHasProperty(pWhere, EP_OuterON|EP_InnerON) /* (9a) */ + && (pSrcList->a[0].fg.jointype & JT_LTORJ)!=0 /* Fast pre-test of (9c) */ + ){ + int jj; + for(jj=0; jj<iSrc; jj++){ + if( pWhere->w.iJoin==pSrcList->a[jj].iCursor ){ + /* If we reach this point, both (9a) and (9b) are satisfied. + ** The following loop checks (9c): + */ + for(jj++; jj<iSrc; jj++){ + if( (pSrcList->a[jj].fg.jointype & JT_RIGHT)!=0 ){ + return 0; /* restriction (9) */ + } + } + } + } + } + if( isLeftJoin + && (ExprHasProperty(pWhere,EP_OuterON)==0 + || pWhere->w.iJoin!=iCursor) + ){ + return 0; /* restriction (4) */ + } + if( ExprHasProperty(pWhere,EP_OuterON) + && pWhere->w.iJoin!=iCursor + ){ + return 0; /* restriction (5) */ + } +#endif + + if( sqlite3ExprIsSingleTableConstraint(pWhere, pSrcList, iSrc) ){ + nChng++; + pSubq->selFlags |= SF_PushDown; + while( pSubq ){ + SubstContext x; + pNew = sqlite3ExprDup(pParse->db, pWhere, 0); + unsetJoinExpr(pNew, -1, 1); + x.pParse = pParse; + x.iTable = pSrc->iCursor; + x.iNewTable = pSrc->iCursor; + x.isOuterJoin = 0; + x.pEList = pSubq->pEList; + x.pCList = findLeftmostExprlist(pSubq); + pNew = substExpr(&x, pNew); +#ifndef SQLITE_OMIT_WINDOWFUNC + if( pSubq->pWin && 0==pushDownWindowCheck(pParse, pSubq, pNew) ){ + /* Restriction 6c has prevented push-down in this case */ + sqlite3ExprDelete(pParse->db, pNew); + nChng--; + break; + } +#endif + if( pSubq->selFlags & SF_Aggregate ){ + pSubq->pHaving = sqlite3ExprAnd(pParse, pSubq->pHaving, pNew); + }else{ + pSubq->pWhere = sqlite3ExprAnd(pParse, pSubq->pWhere, pNew); + } + pSubq = pSubq->pPrior; + } + } + return nChng; +} +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ + +/* +** Check to see if a subquery contains result-set columns that are +** never used. If it does, change the value of those result-set columns +** to NULL so that they do not cause unnecessary work to compute. +** +** Return the number of column that were changed to NULL. +*/ +static int disableUnusedSubqueryResultColumns(SrcItem *pItem){ + int nCol; + Select *pSub; /* The subquery to be simplified */ + Select *pX; /* For looping over compound elements of pSub */ + Table *pTab; /* The table that describes the subquery */ + int j; /* Column number */ + int nChng = 0; /* Number of columns converted to NULL */ + Bitmask colUsed; /* Columns that may not be NULLed out */ + + assert( pItem!=0 ); + if( pItem->fg.isCorrelated || pItem->fg.isCte ){ + return 0; + } + assert( pItem->pTab!=0 ); + pTab = pItem->pTab; + assert( pItem->pSelect!=0 ); + pSub = pItem->pSelect; + assert( pSub->pEList->nExpr==pTab->nCol ); + for(pX=pSub; pX; pX=pX->pPrior){ + if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){ + testcase( pX->selFlags & SF_Distinct ); + testcase( pX->selFlags & SF_Aggregate ); + return 0; + } + if( pX->pPrior && pX->op!=TK_ALL ){ + /* This optimization does not work for compound subqueries that + ** use UNION, INTERSECT, or EXCEPT. Only UNION ALL is allowed. */ + return 0; + } +#ifndef SQLITE_OMIT_WINDOWFUNC + if( pX->pWin ){ + /* This optimization does not work for subqueries that use window + ** functions. */ + return 0; + } +#endif + } + colUsed = pItem->colUsed; + if( pSub->pOrderBy ){ + ExprList *pList = pSub->pOrderBy; + for(j=0; j<pList->nExpr; j++){ + u16 iCol = pList->a[j].u.x.iOrderByCol; + if( iCol>0 ){ + iCol--; + colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol); + } + } + } + nCol = pTab->nCol; + for(j=0; j<nCol; j++){ + Bitmask m = j<BMS-1 ? MASKBIT(j) : TOPBIT; + if( (m & colUsed)!=0 ) continue; + for(pX=pSub; pX; pX=pX->pPrior) { + Expr *pY = pX->pEList->a[j].pExpr; + if( pY->op==TK_NULL ) continue; + pY->op = TK_NULL; + ExprClearProperty(pY, EP_Skip|EP_Unlikely); + pX->selFlags |= SF_PushDown; + nChng++; + } + } + return nChng; +} + + +/* +** The pFunc is the only aggregate function in the query. Check to see +** if the query is a candidate for the min/max optimization. +** +** If the query is a candidate for the min/max optimization, then set +** *ppMinMax to be an ORDER BY clause to be used for the optimization +** and return either WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX depending on +** whether pFunc is a min() or max() function. +** +** If the query is not a candidate for the min/max optimization, return +** WHERE_ORDERBY_NORMAL (which must be zero). +** +** This routine must be called after aggregate functions have been +** located but before their arguments have been subjected to aggregate +** analysis. +*/ +static u8 minMaxQuery(sqlite3 *db, Expr *pFunc, ExprList **ppMinMax){ + int eRet = WHERE_ORDERBY_NORMAL; /* Return value */ + ExprList *pEList; /* Arguments to agg function */ + const char *zFunc; /* Name of aggregate function pFunc */ + ExprList *pOrderBy; + u8 sortFlags = 0; + + assert( *ppMinMax==0 ); + assert( pFunc->op==TK_AGG_FUNCTION ); + assert( !IsWindowFunc(pFunc) ); + assert( ExprUseXList(pFunc) ); + pEList = pFunc->x.pList; + if( pEList==0 + || pEList->nExpr!=1 + || ExprHasProperty(pFunc, EP_WinFunc) + || OptimizationDisabled(db, SQLITE_MinMaxOpt) + ){ + return eRet; + } + assert( !ExprHasProperty(pFunc, EP_IntValue) ); + zFunc = pFunc->u.zToken; + if( sqlite3StrICmp(zFunc, "min")==0 ){ + eRet = WHERE_ORDERBY_MIN; + if( sqlite3ExprCanBeNull(pEList->a[0].pExpr) ){ + sortFlags = KEYINFO_ORDER_BIGNULL; + } + }else if( sqlite3StrICmp(zFunc, "max")==0 ){ + eRet = WHERE_ORDERBY_MAX; + sortFlags = KEYINFO_ORDER_DESC; + }else{ + return eRet; + } + *ppMinMax = pOrderBy = sqlite3ExprListDup(db, pEList, 0); + assert( pOrderBy!=0 || db->mallocFailed ); + if( pOrderBy ) pOrderBy->a[0].fg.sortFlags = sortFlags; + return eRet; +} + +/* +** The select statement passed as the first argument is an aggregate query. +** The second argument is the associated aggregate-info object. This +** function tests if the SELECT is of the form: +** +** SELECT count(*) FROM <tbl> +** +** where table is a database table, not a sub-select or view. If the query +** does match this pattern, then a pointer to the Table object representing +** <tbl> is returned. Otherwise, NULL is returned. +** +** This routine checks to see if it is safe to use the count optimization. +** A correct answer is still obtained (though perhaps more slowly) if +** this routine returns NULL when it could have returned a table pointer. +** But returning the pointer when NULL should have been returned can +** result in incorrect answers and/or crashes. So, when in doubt, return NULL. +*/ +static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){ + Table *pTab; + Expr *pExpr; + + assert( !p->pGroupBy ); + + if( p->pWhere + || p->pEList->nExpr!=1 + || p->pSrc->nSrc!=1 + || p->pSrc->a[0].pSelect + || pAggInfo->nFunc!=1 + || p->pHaving + ){ + return 0; + } + pTab = p->pSrc->a[0].pTab; + assert( pTab!=0 ); + assert( !IsView(pTab) ); + if( !IsOrdinaryTable(pTab) ) return 0; + pExpr = p->pEList->a[0].pExpr; + assert( pExpr!=0 ); + if( pExpr->op!=TK_AGG_FUNCTION ) return 0; + if( pExpr->pAggInfo!=pAggInfo ) return 0; + if( (pAggInfo->aFunc[0].pFunc->funcFlags&SQLITE_FUNC_COUNT)==0 ) return 0; + assert( pAggInfo->aFunc[0].pFExpr==pExpr ); + testcase( ExprHasProperty(pExpr, EP_Distinct) ); + testcase( ExprHasProperty(pExpr, EP_WinFunc) ); + if( ExprHasProperty(pExpr, EP_Distinct|EP_WinFunc) ) return 0; + + return pTab; +} + +/* +** If the source-list item passed as an argument was augmented with an +** INDEXED BY clause, then try to locate the specified index. If there +** was such a clause and the named index cannot be found, return +** SQLITE_ERROR and leave an error in pParse. Otherwise, populate +** pFrom->pIndex and return SQLITE_OK. +*/ +int sqlite3IndexedByLookup(Parse *pParse, SrcItem *pFrom){ + Table *pTab = pFrom->pTab; + char *zIndexedBy = pFrom->u1.zIndexedBy; + Index *pIdx; + assert( pTab!=0 ); + assert( pFrom->fg.isIndexedBy!=0 ); + + for(pIdx=pTab->pIndex; + pIdx && sqlite3StrICmp(pIdx->zName, zIndexedBy); + pIdx=pIdx->pNext + ); + if( !pIdx ){ + sqlite3ErrorMsg(pParse, "no such index: %s", zIndexedBy, 0); + pParse->checkSchema = 1; + return SQLITE_ERROR; + } + assert( pFrom->fg.isCte==0 ); + pFrom->u2.pIBIndex = pIdx; + return SQLITE_OK; +} + +/* +** Detect compound SELECT statements that use an ORDER BY clause with +** an alternative collating sequence. +** +** SELECT ... FROM t1 EXCEPT SELECT ... FROM t2 ORDER BY .. COLLATE ... +** +** These are rewritten as a subquery: +** +** SELECT * FROM (SELECT ... FROM t1 EXCEPT SELECT ... FROM t2) +** ORDER BY ... COLLATE ... +** +** This transformation is necessary because the multiSelectOrderBy() routine +** above that generates the code for a compound SELECT with an ORDER BY clause +** uses a merge algorithm that requires the same collating sequence on the +** result columns as on the ORDER BY clause. See ticket +** http://www.sqlite.org/src/info/6709574d2a +** +** This transformation is only needed for EXCEPT, INTERSECT, and UNION. +** The UNION ALL operator works fine with multiSelectOrderBy() even when +** there are COLLATE terms in the ORDER BY. +*/ +static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){ + int i; + Select *pNew; + Select *pX; + sqlite3 *db; + struct ExprList_item *a; + SrcList *pNewSrc; + Parse *pParse; + Token dummy; + + if( p->pPrior==0 ) return WRC_Continue; + if( p->pOrderBy==0 ) return WRC_Continue; + for(pX=p; pX && (pX->op==TK_ALL || pX->op==TK_SELECT); pX=pX->pPrior){} + if( pX==0 ) return WRC_Continue; + a = p->pOrderBy->a; +#ifndef SQLITE_OMIT_WINDOWFUNC + /* If iOrderByCol is already non-zero, then it has already been matched + ** to a result column of the SELECT statement. This occurs when the + ** SELECT is rewritten for window-functions processing and then passed + ** to sqlite3SelectPrep() and similar a second time. The rewriting done + ** by this function is not required in this case. */ + if( a[0].u.x.iOrderByCol ) return WRC_Continue; +#endif + for(i=p->pOrderBy->nExpr-1; i>=0; i--){ + if( a[i].pExpr->flags & EP_Collate ) break; + } + if( i<0 ) return WRC_Continue; + + /* If we reach this point, that means the transformation is required. */ + + pParse = pWalker->pParse; + db = pParse->db; + pNew = sqlite3DbMallocZero(db, sizeof(*pNew) ); + if( pNew==0 ) return WRC_Abort; + memset(&dummy, 0, sizeof(dummy)); + pNewSrc = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&dummy,pNew,0); + if( pNewSrc==0 ) return WRC_Abort; + *pNew = *p; + p->pSrc = pNewSrc; + p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ASTERISK, 0)); + p->op = TK_SELECT; + p->pWhere = 0; + pNew->pGroupBy = 0; + pNew->pHaving = 0; + pNew->pOrderBy = 0; + p->pPrior = 0; + p->pNext = 0; + p->pWith = 0; +#ifndef SQLITE_OMIT_WINDOWFUNC + p->pWinDefn = 0; +#endif + p->selFlags &= ~SF_Compound; + assert( (p->selFlags & SF_Converted)==0 ); + p->selFlags |= SF_Converted; + assert( pNew->pPrior!=0 ); + pNew->pPrior->pNext = pNew; + pNew->pLimit = 0; + return WRC_Continue; +} + +/* +** Check to see if the FROM clause term pFrom has table-valued function +** arguments. If it does, leave an error message in pParse and return +** non-zero, since pFrom is not allowed to be a table-valued function. +*/ +static int cannotBeFunction(Parse *pParse, SrcItem *pFrom){ + if( pFrom->fg.isTabFunc ){ + sqlite3ErrorMsg(pParse, "'%s' is not a function", pFrom->zName); + return 1; + } + return 0; +} + +#ifndef SQLITE_OMIT_CTE +/* +** Argument pWith (which may be NULL) points to a linked list of nested +** WITH contexts, from inner to outermost. If the table identified by +** FROM clause element pItem is really a common-table-expression (CTE) +** then return a pointer to the CTE definition for that table. Otherwise +** return NULL. +** +** If a non-NULL value is returned, set *ppContext to point to the With +** object that the returned CTE belongs to. +*/ +static struct Cte *searchWith( + With *pWith, /* Current innermost WITH clause */ + SrcItem *pItem, /* FROM clause element to resolve */ + With **ppContext /* OUT: WITH clause return value belongs to */ +){ + const char *zName = pItem->zName; + With *p; + assert( pItem->zDatabase==0 ); + assert( zName!=0 ); + for(p=pWith; p; p=p->pOuter){ + int i; + for(i=0; i<p->nCte; i++){ + if( sqlite3StrICmp(zName, p->a[i].zName)==0 ){ + *ppContext = p; + return &p->a[i]; + } + } + if( p->bView ) break; + } + return 0; +} + +/* The code generator maintains a stack of active WITH clauses +** with the inner-most WITH clause being at the top of the stack. +** +** This routine pushes the WITH clause passed as the second argument +** onto the top of the stack. If argument bFree is true, then this +** WITH clause will never be popped from the stack but should instead +** be freed along with the Parse object. In other cases, when +** bFree==0, the With object will be freed along with the SELECT +** statement with which it is associated. +** +** This routine returns a copy of pWith. Or, if bFree is true and +** the pWith object is destroyed immediately due to an OOM condition, +** then this routine return NULL. +** +** If bFree is true, do not continue to use the pWith pointer after +** calling this routine, Instead, use only the return value. +*/ +With *sqlite3WithPush(Parse *pParse, With *pWith, u8 bFree){ + if( pWith ){ + if( bFree ){ + pWith = (With*)sqlite3ParserAddCleanup(pParse, sqlite3WithDeleteGeneric, + pWith); + if( pWith==0 ) return 0; + } + if( pParse->nErr==0 ){ + assert( pParse->pWith!=pWith ); + pWith->pOuter = pParse->pWith; + pParse->pWith = pWith; + } + } + return pWith; +} + +/* +** This function checks if argument pFrom refers to a CTE declared by +** a WITH clause on the stack currently maintained by the parser (on the +** pParse->pWith linked list). And if currently processing a CTE +** CTE expression, through routine checks to see if the reference is +** a recursive reference to the CTE. +** +** If pFrom matches a CTE according to either of these two above, pFrom->pTab +** and other fields are populated accordingly. +** +** Return 0 if no match is found. +** Return 1 if a match is found. +** Return 2 if an error condition is detected. +*/ +static int resolveFromTermToCte( + Parse *pParse, /* The parsing context */ + Walker *pWalker, /* Current tree walker */ + SrcItem *pFrom /* The FROM clause term to check */ +){ + Cte *pCte; /* Matched CTE (or NULL if no match) */ + With *pWith; /* The matching WITH */ + + assert( pFrom->pTab==0 ); + if( pParse->pWith==0 ){ + /* There are no WITH clauses in the stack. No match is possible */ + return 0; + } + if( pParse->nErr ){ + /* Prior errors might have left pParse->pWith in a goofy state, so + ** go no further. */ + return 0; + } + if( pFrom->zDatabase!=0 ){ + /* The FROM term contains a schema qualifier (ex: main.t1) and so + ** it cannot possibly be a CTE reference. */ + return 0; + } + if( pFrom->fg.notCte ){ + /* The FROM term is specifically excluded from matching a CTE. + ** (1) It is part of a trigger that used to have zDatabase but had + ** zDatabase removed by sqlite3FixTriggerStep(). + ** (2) This is the first term in the FROM clause of an UPDATE. + */ + return 0; + } + pCte = searchWith(pParse->pWith, pFrom, &pWith); + if( pCte ){ + sqlite3 *db = pParse->db; + Table *pTab; + ExprList *pEList; + Select *pSel; + Select *pLeft; /* Left-most SELECT statement */ + Select *pRecTerm; /* Left-most recursive term */ + int bMayRecursive; /* True if compound joined by UNION [ALL] */ + With *pSavedWith; /* Initial value of pParse->pWith */ + int iRecTab = -1; /* Cursor for recursive table */ + CteUse *pCteUse; + + /* If pCte->zCteErr is non-NULL at this point, then this is an illegal + ** recursive reference to CTE pCte. Leave an error in pParse and return + ** early. If pCte->zCteErr is NULL, then this is not a recursive reference. + ** In this case, proceed. */ + if( pCte->zCteErr ){ + sqlite3ErrorMsg(pParse, pCte->zCteErr, pCte->zName); + return 2; + } + if( cannotBeFunction(pParse, pFrom) ) return 2; + + assert( pFrom->pTab==0 ); + pTab = sqlite3DbMallocZero(db, sizeof(Table)); + if( pTab==0 ) return 2; + pCteUse = pCte->pUse; + if( pCteUse==0 ){ + pCte->pUse = pCteUse = sqlite3DbMallocZero(db, sizeof(pCteUse[0])); + if( pCteUse==0 + || sqlite3ParserAddCleanup(pParse,sqlite3DbFree,pCteUse)==0 + ){ + sqlite3DbFree(db, pTab); + return 2; + } + pCteUse->eM10d = pCte->eM10d; + } + pFrom->pTab = pTab; + pTab->nTabRef = 1; + pTab->zName = sqlite3DbStrDup(db, pCte->zName); + pTab->iPKey = -1; + pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) ); + pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid; + pFrom->pSelect = sqlite3SelectDup(db, pCte->pSelect, 0); + if( db->mallocFailed ) return 2; + pFrom->pSelect->selFlags |= SF_CopyCte; + assert( pFrom->pSelect ); + if( pFrom->fg.isIndexedBy ){ + sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy); + return 2; + } + pFrom->fg.isCte = 1; + pFrom->u2.pCteUse = pCteUse; + pCteUse->nUse++; + + /* Check if this is a recursive CTE. */ + pRecTerm = pSel = pFrom->pSelect; + bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION ); + while( bMayRecursive && pRecTerm->op==pSel->op ){ + int i; + SrcList *pSrc = pRecTerm->pSrc; + assert( pRecTerm->pPrior!=0 ); + for(i=0; i<pSrc->nSrc; i++){ + SrcItem *pItem = &pSrc->a[i]; + if( pItem->zDatabase==0 + && pItem->zName!=0 + && 0==sqlite3StrICmp(pItem->zName, pCte->zName) + ){ + pItem->pTab = pTab; + pTab->nTabRef++; + pItem->fg.isRecursive = 1; + if( pRecTerm->selFlags & SF_Recursive ){ + sqlite3ErrorMsg(pParse, + "multiple references to recursive table: %s", pCte->zName + ); + return 2; + } + pRecTerm->selFlags |= SF_Recursive; + if( iRecTab<0 ) iRecTab = pParse->nTab++; + pItem->iCursor = iRecTab; + } + } + if( (pRecTerm->selFlags & SF_Recursive)==0 ) break; + pRecTerm = pRecTerm->pPrior; + } + + pCte->zCteErr = "circular reference: %s"; + pSavedWith = pParse->pWith; + pParse->pWith = pWith; + if( pSel->selFlags & SF_Recursive ){ + int rc; + assert( pRecTerm!=0 ); + assert( (pRecTerm->selFlags & SF_Recursive)==0 ); + assert( pRecTerm->pNext!=0 ); + assert( (pRecTerm->pNext->selFlags & SF_Recursive)!=0 ); + assert( pRecTerm->pWith==0 ); + pRecTerm->pWith = pSel->pWith; + rc = sqlite3WalkSelect(pWalker, pRecTerm); + pRecTerm->pWith = 0; + if( rc ){ + pParse->pWith = pSavedWith; + return 2; + } + }else{ + if( sqlite3WalkSelect(pWalker, pSel) ){ + pParse->pWith = pSavedWith; + return 2; + } + } + pParse->pWith = pWith; + + for(pLeft=pSel; pLeft->pPrior; pLeft=pLeft->pPrior); + pEList = pLeft->pEList; + if( pCte->pCols ){ + if( pEList && pEList->nExpr!=pCte->pCols->nExpr ){ + sqlite3ErrorMsg(pParse, "table %s has %d values for %d columns", + pCte->zName, pEList->nExpr, pCte->pCols->nExpr + ); + pParse->pWith = pSavedWith; + return 2; + } + pEList = pCte->pCols; + } + + sqlite3ColumnsFromExprList(pParse, pEList, &pTab->nCol, &pTab->aCol); + if( bMayRecursive ){ + if( pSel->selFlags & SF_Recursive ){ + pCte->zCteErr = "multiple recursive references: %s"; + }else{ + pCte->zCteErr = "recursive reference in a subquery: %s"; + } + sqlite3WalkSelect(pWalker, pSel); + } + pCte->zCteErr = 0; + pParse->pWith = pSavedWith; + return 1; /* Success */ + } + return 0; /* No match */ +} +#endif + +#ifndef SQLITE_OMIT_CTE +/* +** If the SELECT passed as the second argument has an associated WITH +** clause, pop it from the stack stored as part of the Parse object. +** +** This function is used as the xSelectCallback2() callback by +** sqlite3SelectExpand() when walking a SELECT tree to resolve table +** names and other FROM clause elements. +*/ +void sqlite3SelectPopWith(Walker *pWalker, Select *p){ + Parse *pParse = pWalker->pParse; + if( OK_IF_ALWAYS_TRUE(pParse->pWith) && p->pPrior==0 ){ + With *pWith = findRightmost(p)->pWith; + if( pWith!=0 ){ + assert( pParse->pWith==pWith || pParse->nErr ); + pParse->pWith = pWith->pOuter; + } + } +} +#endif + +/* +** The SrcItem structure passed as the second argument represents a +** sub-query in the FROM clause of a SELECT statement. This function +** allocates and populates the SrcItem.pTab object. If successful, +** SQLITE_OK is returned. Otherwise, if an OOM error is encountered, +** SQLITE_NOMEM. +*/ +int sqlite3ExpandSubquery(Parse *pParse, SrcItem *pFrom){ + Select *pSel = pFrom->pSelect; + Table *pTab; + + assert( pSel ); + pFrom->pTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table)); + if( pTab==0 ) return SQLITE_NOMEM; + pTab->nTabRef = 1; + if( pFrom->zAlias ){ + pTab->zName = sqlite3DbStrDup(pParse->db, pFrom->zAlias); + }else{ + pTab->zName = sqlite3MPrintf(pParse->db, "%!S", pFrom); + } + while( pSel->pPrior ){ pSel = pSel->pPrior; } + sqlite3ColumnsFromExprList(pParse, pSel->pEList,&pTab->nCol,&pTab->aCol); + pTab->iPKey = -1; + pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) ); +#ifndef SQLITE_ALLOW_ROWID_IN_VIEW + /* The usual case - do not allow ROWID on a subquery */ + pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid; +#else + pTab->tabFlags |= TF_Ephemeral; /* Legacy compatibility mode */ +#endif + return pParse->nErr ? SQLITE_ERROR : SQLITE_OK; +} + + +/* +** Check the N SrcItem objects to the right of pBase. (N might be zero!) +** If any of those SrcItem objects have a USING clause containing zName +** then return true. +** +** If N is zero, or none of the N SrcItem objects to the right of pBase +** contains a USING clause, or if none of the USING clauses contain zName, +** then return false. +*/ +static int inAnyUsingClause( + const char *zName, /* Name we are looking for */ + SrcItem *pBase, /* The base SrcItem. Looking at pBase[1] and following */ + int N /* How many SrcItems to check */ +){ + while( N>0 ){ + N--; + pBase++; + if( pBase->fg.isUsing==0 ) continue; + if( NEVER(pBase->u3.pUsing==0) ) continue; + if( sqlite3IdListIndex(pBase->u3.pUsing, zName)>=0 ) return 1; + } + return 0; +} + + +/* +** This routine is a Walker callback for "expanding" a SELECT statement. +** "Expanding" means to do the following: +** +** (1) Make sure VDBE cursor numbers have been assigned to every +** element of the FROM clause. +** +** (2) Fill in the pTabList->a[].pTab fields in the SrcList that +** defines FROM clause. When views appear in the FROM clause, +** fill pTabList->a[].pSelect with a copy of the SELECT statement +** that implements the view. A copy is made of the view's SELECT +** statement so that we can freely modify or delete that statement +** without worrying about messing up the persistent representation +** of the view. +** +** (3) Add terms to the WHERE clause to accommodate the NATURAL keyword +** on joins and the ON and USING clause of joins. +** +** (4) Scan the list of columns in the result set (pEList) looking +** for instances of the "*" operator or the TABLE.* operator. +** If found, expand each "*" to be every column in every table +** and TABLE.* to be every column in TABLE. +** +*/ +static int selectExpander(Walker *pWalker, Select *p){ + Parse *pParse = pWalker->pParse; + int i, j, k, rc; + SrcList *pTabList; + ExprList *pEList; + SrcItem *pFrom; + sqlite3 *db = pParse->db; + Expr *pE, *pRight, *pExpr; + u16 selFlags = p->selFlags; + u32 elistFlags = 0; + + p->selFlags |= SF_Expanded; + if( db->mallocFailed ){ + return WRC_Abort; + } + assert( p->pSrc!=0 ); + if( (selFlags & SF_Expanded)!=0 ){ + return WRC_Prune; + } + if( pWalker->eCode ){ + /* Renumber selId because it has been copied from a view */ + p->selId = ++pParse->nSelect; + } + pTabList = p->pSrc; + pEList = p->pEList; + if( pParse->pWith && (p->selFlags & SF_View) ){ + if( p->pWith==0 ){ + p->pWith = (With*)sqlite3DbMallocZero(db, sizeof(With)); + if( p->pWith==0 ){ + return WRC_Abort; + } + } + p->pWith->bView = 1; + } + sqlite3WithPush(pParse, p->pWith, 0); + + /* Make sure cursor numbers have been assigned to all entries in + ** the FROM clause of the SELECT statement. + */ + sqlite3SrcListAssignCursors(pParse, pTabList); + + /* Look up every table named in the FROM clause of the select. If + ** an entry of the FROM clause is a subquery instead of a table or view, + ** then create a transient table structure to describe the subquery. + */ + for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){ + Table *pTab; + assert( pFrom->fg.isRecursive==0 || pFrom->pTab!=0 ); + if( pFrom->pTab ) continue; + assert( pFrom->fg.isRecursive==0 ); + if( pFrom->zName==0 ){ +#ifndef SQLITE_OMIT_SUBQUERY + Select *pSel = pFrom->pSelect; + /* A sub-query in the FROM clause of a SELECT */ + assert( pSel!=0 ); + assert( pFrom->pTab==0 ); + if( sqlite3WalkSelect(pWalker, pSel) ) return WRC_Abort; + if( sqlite3ExpandSubquery(pParse, pFrom) ) return WRC_Abort; +#endif +#ifndef SQLITE_OMIT_CTE + }else if( (rc = resolveFromTermToCte(pParse, pWalker, pFrom))!=0 ){ + if( rc>1 ) return WRC_Abort; + pTab = pFrom->pTab; + assert( pTab!=0 ); +#endif + }else{ + /* An ordinary table or view name in the FROM clause */ + assert( pFrom->pTab==0 ); + pFrom->pTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom); + if( pTab==0 ) return WRC_Abort; + if( pTab->nTabRef>=0xffff ){ + sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535", + pTab->zName); + pFrom->pTab = 0; + return WRC_Abort; + } + pTab->nTabRef++; + if( !IsVirtual(pTab) && cannotBeFunction(pParse, pFrom) ){ + return WRC_Abort; + } +#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) + if( !IsOrdinaryTable(pTab) ){ + i16 nCol; + u8 eCodeOrig = pWalker->eCode; + if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort; + assert( pFrom->pSelect==0 ); + if( IsView(pTab) ){ + if( (db->flags & SQLITE_EnableView)==0 + && pTab->pSchema!=db->aDb[1].pSchema + ){ + sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited", + pTab->zName); + } + pFrom->pSelect = sqlite3SelectDup(db, pTab->u.view.pSelect, 0); + } +#ifndef SQLITE_OMIT_VIRTUALTABLE + else if( ALWAYS(IsVirtual(pTab)) + && pFrom->fg.fromDDL + && ALWAYS(pTab->u.vtab.p!=0) + && pTab->u.vtab.p->eVtabRisk > ((db->flags & SQLITE_TrustedSchema)!=0) + ){ + sqlite3ErrorMsg(pParse, "unsafe use of virtual table \"%s\"", + pTab->zName); + } + assert( SQLITE_VTABRISK_Normal==1 && SQLITE_VTABRISK_High==2 ); +#endif + nCol = pTab->nCol; + pTab->nCol = -1; + pWalker->eCode = 1; /* Turn on Select.selId renumbering */ + sqlite3WalkSelect(pWalker, pFrom->pSelect); + pWalker->eCode = eCodeOrig; + pTab->nCol = nCol; + } +#endif + } + + /* Locate the index named by the INDEXED BY clause, if any. */ + if( pFrom->fg.isIndexedBy && sqlite3IndexedByLookup(pParse, pFrom) ){ + return WRC_Abort; + } + } + + /* Process NATURAL keywords, and ON and USING clauses of joins. + */ + assert( db->mallocFailed==0 || pParse->nErr!=0 ); + if( pParse->nErr || sqlite3ProcessJoin(pParse, p) ){ + return WRC_Abort; + } + + /* For every "*" that occurs in the column list, insert the names of + ** all columns in all tables. And for every TABLE.* insert the names + ** of all columns in TABLE. The parser inserted a special expression + ** with the TK_ASTERISK operator for each "*" that it found in the column + ** list. The following code just has to locate the TK_ASTERISK + ** expressions and expand each one to the list of all columns in + ** all tables. + ** + ** The first loop just checks to see if there are any "*" operators + ** that need expanding. + */ + for(k=0; k<pEList->nExpr; k++){ + pE = pEList->a[k].pExpr; + if( pE->op==TK_ASTERISK ) break; + assert( pE->op!=TK_DOT || pE->pRight!=0 ); + assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) ); + if( pE->op==TK_DOT && pE->pRight->op==TK_ASTERISK ) break; + elistFlags |= pE->flags; + } + if( k<pEList->nExpr ){ + /* + ** If we get here it means the result set contains one or more "*" + ** operators that need to be expanded. Loop through each expression + ** in the result set and expand them one by one. + */ + struct ExprList_item *a = pEList->a; + ExprList *pNew = 0; + int flags = pParse->db->flags; + int longNames = (flags & SQLITE_FullColNames)!=0 + && (flags & SQLITE_ShortColNames)==0; + + for(k=0; k<pEList->nExpr; k++){ + pE = a[k].pExpr; + elistFlags |= pE->flags; + pRight = pE->pRight; + assert( pE->op!=TK_DOT || pRight!=0 ); + if( pE->op!=TK_ASTERISK + && (pE->op!=TK_DOT || pRight->op!=TK_ASTERISK) + ){ + /* This particular expression does not need to be expanded. + */ + pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr); + if( pNew ){ + pNew->a[pNew->nExpr-1].zEName = a[k].zEName; + pNew->a[pNew->nExpr-1].fg.eEName = a[k].fg.eEName; + a[k].zEName = 0; + } + a[k].pExpr = 0; + }else{ + /* This expression is a "*" or a "TABLE.*" and needs to be + ** expanded. */ + int tableSeen = 0; /* Set to 1 when TABLE matches */ + char *zTName = 0; /* text of name of TABLE */ + int iErrOfst; + if( pE->op==TK_DOT ){ + assert( (selFlags & SF_NestedFrom)==0 ); + assert( pE->pLeft!=0 ); + assert( !ExprHasProperty(pE->pLeft, EP_IntValue) ); + zTName = pE->pLeft->u.zToken; + assert( ExprUseWOfst(pE->pLeft) ); + iErrOfst = pE->pRight->w.iOfst; + }else{ + assert( ExprUseWOfst(pE) ); + iErrOfst = pE->w.iOfst; + } + for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){ + int nAdd; /* Number of cols including rowid */ + Table *pTab = pFrom->pTab; /* Table for this data source */ + ExprList *pNestedFrom; /* Result-set of a nested FROM clause */ + char *zTabName; /* AS name for this data source */ + const char *zSchemaName = 0; /* Schema name for this data source */ + int iDb; /* Schema index for this data src */ + IdList *pUsing; /* USING clause for pFrom[1] */ + + if( (zTabName = pFrom->zAlias)==0 ){ + zTabName = pTab->zName; + } + if( db->mallocFailed ) break; + assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom->pSelect) ); + if( pFrom->fg.isNestedFrom ){ + assert( pFrom->pSelect!=0 ); + pNestedFrom = pFrom->pSelect->pEList; + assert( pNestedFrom!=0 ); + assert( pNestedFrom->nExpr==pTab->nCol ); + assert( VisibleRowid(pTab)==0 ); + }else{ + if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){ + continue; + } + pNestedFrom = 0; + iDb = sqlite3SchemaToIndex(db, pTab->pSchema); + zSchemaName = iDb>=0 ? db->aDb[iDb].zDbSName : "*"; + } + if( i+1<pTabList->nSrc + && pFrom[1].fg.isUsing + && (selFlags & SF_NestedFrom)!=0 + ){ + int ii; + pUsing = pFrom[1].u3.pUsing; + for(ii=0; ii<pUsing->nId; ii++){ + const char *zUName = pUsing->a[ii].zName; + pRight = sqlite3Expr(db, TK_ID, zUName); + sqlite3ExprSetErrorOffset(pRight, iErrOfst); + pNew = sqlite3ExprListAppend(pParse, pNew, pRight); + if( pNew ){ + struct ExprList_item *pX = &pNew->a[pNew->nExpr-1]; + assert( pX->zEName==0 ); + pX->zEName = sqlite3MPrintf(db,"..%s", zUName); + pX->fg.eEName = ENAME_TAB; + pX->fg.bUsingTerm = 1; + } + } + }else{ + pUsing = 0; + } + + nAdd = pTab->nCol + (VisibleRowid(pTab) && (selFlags&SF_NestedFrom)); + for(j=0; j<nAdd; j++){ + const char *zName; + struct ExprList_item *pX; /* Newly added ExprList term */ + + if( j==pTab->nCol ){ + zName = sqlite3RowidAlias(pTab); + if( zName==0 ) continue; + }else{ + zName = pTab->aCol[j].zCnName; + + /* If pTab is actually an SF_NestedFrom sub-select, do not + ** expand any ENAME_ROWID columns. */ + if( pNestedFrom && pNestedFrom->a[j].fg.eEName==ENAME_ROWID ){ + continue; + } + + if( zTName + && pNestedFrom + && sqlite3MatchEName(&pNestedFrom->a[j], 0, zTName, 0, 0)==0 + ){ + continue; + } + + /* If a column is marked as 'hidden', omit it from the expanded + ** result-set list unless the SELECT has the SF_IncludeHidden + ** bit set. + */ + if( (p->selFlags & SF_IncludeHidden)==0 + && IsHiddenColumn(&pTab->aCol[j]) + ){ + continue; + } + if( (pTab->aCol[j].colFlags & COLFLAG_NOEXPAND)!=0 + && zTName==0 + && (selFlags & (SF_NestedFrom))==0 + ){ + continue; + } + } + assert( zName ); + tableSeen = 1; + + if( i>0 && zTName==0 && (selFlags & SF_NestedFrom)==0 ){ + if( pFrom->fg.isUsing + && sqlite3IdListIndex(pFrom->u3.pUsing, zName)>=0 + ){ + /* In a join with a USING clause, omit columns in the + ** using clause from the table on the right. */ + continue; + } + } + pRight = sqlite3Expr(db, TK_ID, zName); + if( (pTabList->nSrc>1 + && ( (pFrom->fg.jointype & JT_LTORJ)==0 + || (selFlags & SF_NestedFrom)!=0 + || !inAnyUsingClause(zName,pFrom,pTabList->nSrc-i-1) + ) + ) + || IN_RENAME_OBJECT + ){ + Expr *pLeft; + pLeft = sqlite3Expr(db, TK_ID, zTabName); + pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight); + if( IN_RENAME_OBJECT && pE->pLeft ){ + sqlite3RenameTokenRemap(pParse, pLeft, pE->pLeft); + } + if( zSchemaName ){ + pLeft = sqlite3Expr(db, TK_ID, zSchemaName); + pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pExpr); + } + }else{ + pExpr = pRight; + } + sqlite3ExprSetErrorOffset(pExpr, iErrOfst); + pNew = sqlite3ExprListAppend(pParse, pNew, pExpr); + if( pNew==0 ){ + break; /* OOM */ + } + pX = &pNew->a[pNew->nExpr-1]; + assert( pX->zEName==0 ); + if( (selFlags & SF_NestedFrom)!=0 && !IN_RENAME_OBJECT ){ + if( pNestedFrom ){ + pX->zEName = sqlite3DbStrDup(db, pNestedFrom->a[j].zEName); + testcase( pX->zEName==0 ); + }else{ + pX->zEName = sqlite3MPrintf(db, "%s.%s.%s", + zSchemaName, zTabName, zName); + testcase( pX->zEName==0 ); + } + pX->fg.eEName = (j==pTab->nCol ? ENAME_ROWID : ENAME_TAB); + if( (pFrom->fg.isUsing + && sqlite3IdListIndex(pFrom->u3.pUsing, zName)>=0) + || (pUsing && sqlite3IdListIndex(pUsing, zName)>=0) + || (j<pTab->nCol && (pTab->aCol[j].colFlags & COLFLAG_NOEXPAND)) + ){ + pX->fg.bNoExpand = 1; + } + }else if( longNames ){ + pX->zEName = sqlite3MPrintf(db, "%s.%s", zTabName, zName); + pX->fg.eEName = ENAME_NAME; + }else{ + pX->zEName = sqlite3DbStrDup(db, zName); + pX->fg.eEName = ENAME_NAME; + } + } + } + if( !tableSeen ){ + if( zTName ){ + sqlite3ErrorMsg(pParse, "no such table: %s", zTName); + }else{ + sqlite3ErrorMsg(pParse, "no tables specified"); + } + } + } + } + sqlite3ExprListDelete(db, pEList); + p->pEList = pNew; + } + if( p->pEList ){ + if( p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){ + sqlite3ErrorMsg(pParse, "too many columns in result set"); + return WRC_Abort; + } + if( (elistFlags & (EP_HasFunc|EP_Subquery))!=0 ){ + p->selFlags |= SF_ComplexResult; + } + } +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x8 ){ + TREETRACE(0x8,pParse,p,("After result-set wildcard expansion:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + return WRC_Continue; +} + +#if SQLITE_DEBUG +/* +** Always assert. This xSelectCallback2 implementation proves that the +** xSelectCallback2 is never invoked. +*/ +void sqlite3SelectWalkAssert2(Walker *NotUsed, Select *NotUsed2){ + UNUSED_PARAMETER2(NotUsed, NotUsed2); + assert( 0 ); +} +#endif +/* +** This routine "expands" a SELECT statement and all of its subqueries. +** For additional information on what it means to "expand" a SELECT +** statement, see the comment on the selectExpand worker callback above. +** +** Expanding a SELECT statement is the first step in processing a +** SELECT statement. The SELECT statement must be expanded before +** name resolution is performed. +** +** If anything goes wrong, an error message is written into pParse. +** The calling function can detect the problem by looking at pParse->nErr +** and/or pParse->db->mallocFailed. +*/ +static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){ + Walker w; + w.xExprCallback = sqlite3ExprWalkNoop; + w.pParse = pParse; + if( OK_IF_ALWAYS_TRUE(pParse->hasCompound) ){ + w.xSelectCallback = convertCompoundSelectToSubquery; + w.xSelectCallback2 = 0; + sqlite3WalkSelect(&w, pSelect); + } + w.xSelectCallback = selectExpander; + w.xSelectCallback2 = sqlite3SelectPopWith; + w.eCode = 0; + sqlite3WalkSelect(&w, pSelect); +} + + +#ifndef SQLITE_OMIT_SUBQUERY +/* +** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo() +** interface. +** +** For each FROM-clause subquery, add Column.zType, Column.zColl, and +** Column.affinity information to the Table structure that represents +** the result set of that subquery. +** +** The Table structure that represents the result set was constructed +** by selectExpander() but the type and collation and affinity information +** was omitted at that point because identifiers had not yet been resolved. +** This routine is called after identifier resolution. +*/ +static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){ + Parse *pParse; + int i; + SrcList *pTabList; + SrcItem *pFrom; + + if( p->selFlags & SF_HasTypeInfo ) return; + p->selFlags |= SF_HasTypeInfo; + pParse = pWalker->pParse; + testcase( (p->selFlags & SF_Resolved)==0 ); + assert( (p->selFlags & SF_Resolved) || IN_RENAME_OBJECT ); + pTabList = p->pSrc; + for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){ + Table *pTab = pFrom->pTab; + assert( pTab!=0 ); + if( (pTab->tabFlags & TF_Ephemeral)!=0 ){ + /* A sub-query in the FROM clause of a SELECT */ + Select *pSel = pFrom->pSelect; + if( pSel ){ + sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE); + } + } + } +} +#endif + + +/* +** This routine adds datatype and collating sequence information to +** the Table structures of all FROM-clause subqueries in a +** SELECT statement. +** +** Use this routine after name resolution. +*/ +static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){ +#ifndef SQLITE_OMIT_SUBQUERY + Walker w; + w.xSelectCallback = sqlite3SelectWalkNoop; + w.xSelectCallback2 = selectAddSubqueryTypeInfo; + w.xExprCallback = sqlite3ExprWalkNoop; + w.pParse = pParse; + sqlite3WalkSelect(&w, pSelect); +#endif +} + + +/* +** This routine sets up a SELECT statement for processing. The +** following is accomplished: +** +** * VDBE Cursor numbers are assigned to all FROM-clause terms. +** * Ephemeral Table objects are created for all FROM-clause subqueries. +** * ON and USING clauses are shifted into WHERE statements +** * Wildcards "*" and "TABLE.*" in result sets are expanded. +** * Identifiers in expression are matched to tables. +** +** This routine acts recursively on all subqueries within the SELECT. +*/ +void sqlite3SelectPrep( + Parse *pParse, /* The parser context */ + Select *p, /* The SELECT statement being coded. */ + NameContext *pOuterNC /* Name context for container */ +){ + assert( p!=0 || pParse->db->mallocFailed ); + assert( pParse->db->pParse==pParse ); + if( pParse->db->mallocFailed ) return; + if( p->selFlags & SF_HasTypeInfo ) return; + sqlite3SelectExpand(pParse, p); + if( pParse->nErr ) return; + sqlite3ResolveSelectNames(pParse, p, pOuterNC); + if( pParse->nErr ) return; + sqlite3SelectAddTypeInfo(pParse, p); +} + +#if TREETRACE_ENABLED +/* +** Display all information about an AggInfo object +*/ +static void printAggInfo(AggInfo *pAggInfo){ + int ii; + for(ii=0; ii<pAggInfo->nColumn; ii++){ + struct AggInfo_col *pCol = &pAggInfo->aCol[ii]; + sqlite3DebugPrintf( + "agg-column[%d] pTab=%s iTable=%d iColumn=%d iMem=%d" + " iSorterColumn=%d %s\n", + ii, pCol->pTab ? pCol->pTab->zName : "NULL", + pCol->iTable, pCol->iColumn, pAggInfo->iFirstReg+ii, + pCol->iSorterColumn, + ii>=pAggInfo->nAccumulator ? "" : " Accumulator"); + sqlite3TreeViewExpr(0, pAggInfo->aCol[ii].pCExpr, 0); + } + for(ii=0; ii<pAggInfo->nFunc; ii++){ + sqlite3DebugPrintf("agg-func[%d]: iMem=%d\n", + ii, pAggInfo->iFirstReg+pAggInfo->nColumn+ii); + sqlite3TreeViewExpr(0, pAggInfo->aFunc[ii].pFExpr, 0); + } +} +#endif /* TREETRACE_ENABLED */ + +/* +** Analyze the arguments to aggregate functions. Create new pAggInfo->aCol[] +** entries for columns that are arguments to aggregate functions but which +** are not otherwise used. +** +** The aCol[] entries in AggInfo prior to nAccumulator are columns that +** are referenced outside of aggregate functions. These might be columns +** that are part of the GROUP by clause, for example. Other database engines +** would throw an error if there is a column reference that is not in the +** GROUP BY clause and that is not part of an aggregate function argument. +** But SQLite allows this. +** +** The aCol[] entries beginning with the aCol[nAccumulator] and following +** are column references that are used exclusively as arguments to +** aggregate functions. This routine is responsible for computing +** (or recomputing) those aCol[] entries. +*/ +static void analyzeAggFuncArgs( + AggInfo *pAggInfo, + NameContext *pNC +){ + int i; + assert( pAggInfo!=0 ); + assert( pAggInfo->iFirstReg==0 ); + pNC->ncFlags |= NC_InAggFunc; + for(i=0; i<pAggInfo->nFunc; i++){ + Expr *pExpr = pAggInfo->aFunc[i].pFExpr; + assert( pExpr->op==TK_FUNCTION || pExpr->op==TK_AGG_FUNCTION ); + assert( ExprUseXList(pExpr) ); + sqlite3ExprAnalyzeAggList(pNC, pExpr->x.pList); + if( pExpr->pLeft ){ + assert( pExpr->pLeft->op==TK_ORDER ); + assert( ExprUseXList(pExpr->pLeft) ); + sqlite3ExprAnalyzeAggList(pNC, pExpr->pLeft->x.pList); + } +#ifndef SQLITE_OMIT_WINDOWFUNC + assert( !IsWindowFunc(pExpr) ); + if( ExprHasProperty(pExpr, EP_WinFunc) ){ + sqlite3ExprAnalyzeAggregates(pNC, pExpr->y.pWin->pFilter); + } +#endif + } + pNC->ncFlags &= ~NC_InAggFunc; +} + +/* +** An index on expressions is being used in the inner loop of an +** aggregate query with a GROUP BY clause. This routine attempts +** to adjust the AggInfo object to take advantage of index and to +** perhaps use the index as a covering index. +** +*/ +static void optimizeAggregateUseOfIndexedExpr( + Parse *pParse, /* Parsing context */ + Select *pSelect, /* The SELECT statement being processed */ + AggInfo *pAggInfo, /* The aggregate info */ + NameContext *pNC /* Name context used to resolve agg-func args */ +){ + assert( pAggInfo->iFirstReg==0 ); + assert( pSelect!=0 ); + assert( pSelect->pGroupBy!=0 ); + pAggInfo->nColumn = pAggInfo->nAccumulator; + if( ALWAYS(pAggInfo->nSortingColumn>0) ){ + int mx = pSelect->pGroupBy->nExpr - 1; + int j, k; + for(j=0; j<pAggInfo->nColumn; j++){ + k = pAggInfo->aCol[j].iSorterColumn; + if( k>mx ) mx = k; + } + pAggInfo->nSortingColumn = mx+1; + } + analyzeAggFuncArgs(pAggInfo, pNC); +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x20 ){ + IndexedExpr *pIEpr; + TREETRACE(0x20, pParse, pSelect, + ("AggInfo (possibly) adjusted for Indexed Exprs\n")); + sqlite3TreeViewSelect(0, pSelect, 0); + for(pIEpr=pParse->pIdxEpr; pIEpr; pIEpr=pIEpr->pIENext){ + printf("data-cursor=%d index={%d,%d}\n", + pIEpr->iDataCur, pIEpr->iIdxCur, pIEpr->iIdxCol); + sqlite3TreeViewExpr(0, pIEpr->pExpr, 0); + } + printAggInfo(pAggInfo); + } +#else + UNUSED_PARAMETER(pSelect); + UNUSED_PARAMETER(pParse); +#endif +} + +/* +** Walker callback for aggregateConvertIndexedExprRefToColumn(). +*/ +static int aggregateIdxEprRefToColCallback(Walker *pWalker, Expr *pExpr){ + AggInfo *pAggInfo; + struct AggInfo_col *pCol; + UNUSED_PARAMETER(pWalker); + if( pExpr->pAggInfo==0 ) return WRC_Continue; + if( pExpr->op==TK_AGG_COLUMN ) return WRC_Continue; + if( pExpr->op==TK_AGG_FUNCTION ) return WRC_Continue; + if( pExpr->op==TK_IF_NULL_ROW ) return WRC_Continue; + pAggInfo = pExpr->pAggInfo; + if( NEVER(pExpr->iAgg>=pAggInfo->nColumn) ) return WRC_Continue; + assert( pExpr->iAgg>=0 ); + pCol = &pAggInfo->aCol[pExpr->iAgg]; + pExpr->op = TK_AGG_COLUMN; + pExpr->iTable = pCol->iTable; + pExpr->iColumn = pCol->iColumn; + ExprClearProperty(pExpr, EP_Skip|EP_Collate|EP_Unlikely); + return WRC_Prune; +} + +/* +** Convert every pAggInfo->aFunc[].pExpr such that any node within +** those expressions that has pAppInfo set is changed into a TK_AGG_COLUMN +** opcode. +*/ +static void aggregateConvertIndexedExprRefToColumn(AggInfo *pAggInfo){ + int i; + Walker w; + memset(&w, 0, sizeof(w)); + w.xExprCallback = aggregateIdxEprRefToColCallback; + for(i=0; i<pAggInfo->nFunc; i++){ + sqlite3WalkExpr(&w, pAggInfo->aFunc[i].pFExpr); + } +} + + +/* +** Allocate a block of registers so that there is one register for each +** pAggInfo->aCol[] and pAggInfo->aFunc[] entry in pAggInfo. The first +** register in this block is stored in pAggInfo->iFirstReg. +** +** This routine may only be called once for each AggInfo object. Prior +** to calling this routine: +** +** * The aCol[] and aFunc[] arrays may be modified +** * The AggInfoColumnReg() and AggInfoFuncReg() macros may not be used +** +** After calling this routine: +** +** * The aCol[] and aFunc[] arrays are fixed +** * The AggInfoColumnReg() and AggInfoFuncReg() macros may be used +** +*/ +static void assignAggregateRegisters(Parse *pParse, AggInfo *pAggInfo){ + assert( pAggInfo!=0 ); + assert( pAggInfo->iFirstReg==0 ); + pAggInfo->iFirstReg = pParse->nMem + 1; + pParse->nMem += pAggInfo->nColumn + pAggInfo->nFunc; +} + +/* +** Reset the aggregate accumulator. +** +** The aggregate accumulator is a set of memory cells that hold +** intermediate results while calculating an aggregate. This +** routine generates code that stores NULLs in all of those memory +** cells. +*/ +static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){ + Vdbe *v = pParse->pVdbe; + int i; + struct AggInfo_func *pFunc; + int nReg = pAggInfo->nFunc + pAggInfo->nColumn; + assert( pAggInfo->iFirstReg>0 ); + assert( pParse->db->pParse==pParse ); + assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 ); + if( nReg==0 ) return; + if( pParse->nErr ) return; + sqlite3VdbeAddOp3(v, OP_Null, 0, pAggInfo->iFirstReg, + pAggInfo->iFirstReg+nReg-1); + for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){ + if( pFunc->iDistinct>=0 ){ + Expr *pE = pFunc->pFExpr; + assert( ExprUseXList(pE) ); + if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){ + sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one " + "argument"); + pFunc->iDistinct = -1; + }else{ + KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pE->x.pList,0,0); + pFunc->iDistAddr = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, + pFunc->iDistinct, 0, 0, (char*)pKeyInfo, P4_KEYINFO); + ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s(DISTINCT)", + pFunc->pFunc->zName)); + } + } + if( pFunc->iOBTab>=0 ){ + ExprList *pOBList; + KeyInfo *pKeyInfo; + int nExtra = 0; + assert( pFunc->pFExpr->pLeft!=0 ); + assert( pFunc->pFExpr->pLeft->op==TK_ORDER ); + assert( ExprUseXList(pFunc->pFExpr->pLeft) ); + assert( pFunc->pFunc!=0 ); + pOBList = pFunc->pFExpr->pLeft->x.pList; + if( !pFunc->bOBUnique ){ + nExtra++; /* One extra column for the OP_Sequence */ + } + if( pFunc->bOBPayload ){ + /* extra columns for the function arguments */ + assert( ExprUseXList(pFunc->pFExpr) ); + nExtra += pFunc->pFExpr->x.pList->nExpr; + } + if( pFunc->bUseSubtype ){ + nExtra += pFunc->pFExpr->x.pList->nExpr; + } + pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOBList, 0, nExtra); + if( !pFunc->bOBUnique && pParse->nErr==0 ){ + pKeyInfo->nKeyField++; + } + sqlite3VdbeAddOp4(v, OP_OpenEphemeral, + pFunc->iOBTab, pOBList->nExpr+nExtra, 0, + (char*)pKeyInfo, P4_KEYINFO); + ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s(ORDER BY)", + pFunc->pFunc->zName)); + } + } +} + +/* +** Invoke the OP_AggFinalize opcode for every aggregate function +** in the AggInfo structure. +*/ +static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){ + Vdbe *v = pParse->pVdbe; + int i; + struct AggInfo_func *pF; + for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){ + ExprList *pList; + assert( ExprUseXList(pF->pFExpr) ); + pList = pF->pFExpr->x.pList; + if( pF->iOBTab>=0 ){ + /* For an ORDER BY aggregate, calls to OP_AggStep were deferred. Inputs + ** were stored in emphermal table pF->iOBTab. Here, we extract those + ** inputs (in ORDER BY order) and make all calls to OP_AggStep + ** before doing the OP_AggFinal call. */ + int iTop; /* Start of loop for extracting columns */ + int nArg; /* Number of columns to extract */ + int nKey; /* Key columns to be skipped */ + int regAgg; /* Extract into this array */ + int j; /* Loop counter */ + + assert( pF->pFunc!=0 ); + nArg = pList->nExpr; + regAgg = sqlite3GetTempRange(pParse, nArg); + + if( pF->bOBPayload==0 ){ + nKey = 0; + }else{ + assert( pF->pFExpr->pLeft!=0 ); + assert( ExprUseXList(pF->pFExpr->pLeft) ); + assert( pF->pFExpr->pLeft->x.pList!=0 ); + nKey = pF->pFExpr->pLeft->x.pList->nExpr; + if( ALWAYS(!pF->bOBUnique) ) nKey++; + } + iTop = sqlite3VdbeAddOp1(v, OP_Rewind, pF->iOBTab); VdbeCoverage(v); + for(j=nArg-1; j>=0; j--){ + sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, nKey+j, regAgg+j); + } + if( pF->bUseSubtype ){ + int regSubtype = sqlite3GetTempReg(pParse); + int iBaseCol = nKey + nArg + (pF->bOBPayload==0 && pF->bOBUnique==0); + for(j=nArg-1; j>=0; j--){ + sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, iBaseCol+j, regSubtype); + sqlite3VdbeAddOp2(v, OP_SetSubtype, regSubtype, regAgg+j); + } + sqlite3ReleaseTempReg(pParse, regSubtype); + } + sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i)); + sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, (u8)nArg); + sqlite3VdbeAddOp2(v, OP_Next, pF->iOBTab, iTop+1); VdbeCoverage(v); + sqlite3VdbeJumpHere(v, iTop); + sqlite3ReleaseTempRange(pParse, regAgg, nArg); + } + sqlite3VdbeAddOp2(v, OP_AggFinal, AggInfoFuncReg(pAggInfo,i), + pList ? pList->nExpr : 0); + sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF); + } +} + +/* +** Generate code that will update the accumulator memory cells for an +** aggregate based on the current cursor position. +** +** If regAcc is non-zero and there are no min() or max() aggregates +** in pAggInfo, then only populate the pAggInfo->nAccumulator accumulator +** registers if register regAcc contains 0. The caller will take care +** of setting and clearing regAcc. +** +** For an ORDER BY aggregate, the actual accumulator memory cell update +** is deferred until after all input rows have been received, so that they +** can be run in the requested order. In that case, instead of invoking +** OP_AggStep to update the accumulator, just add the arguments that would +** have been passed into OP_AggStep into the sorting ephemeral table +** (along with the appropriate sort key). +*/ +static void updateAccumulator( + Parse *pParse, + int regAcc, + AggInfo *pAggInfo, + int eDistinctType +){ + Vdbe *v = pParse->pVdbe; + int i; + int regHit = 0; + int addrHitTest = 0; + struct AggInfo_func *pF; + struct AggInfo_col *pC; + + assert( pAggInfo->iFirstReg>0 ); + if( pParse->nErr ) return; + pAggInfo->directMode = 1; + for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){ + int nArg; + int addrNext = 0; + int regAgg; + int regAggSz = 0; + int regDistinct = 0; + ExprList *pList; + assert( ExprUseXList(pF->pFExpr) ); + assert( !IsWindowFunc(pF->pFExpr) ); + assert( pF->pFunc!=0 ); + pList = pF->pFExpr->x.pList; + if( ExprHasProperty(pF->pFExpr, EP_WinFunc) ){ + Expr *pFilter = pF->pFExpr->y.pWin->pFilter; + if( pAggInfo->nAccumulator + && (pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL) + && regAcc + ){ + /* If regAcc==0, there there exists some min() or max() function + ** without a FILTER clause that will ensure the magnet registers + ** are populated. */ + if( regHit==0 ) regHit = ++pParse->nMem; + /* If this is the first row of the group (regAcc contains 0), clear the + ** "magnet" register regHit so that the accumulator registers + ** are populated if the FILTER clause jumps over the the + ** invocation of min() or max() altogether. Or, if this is not + ** the first row (regAcc contains 1), set the magnet register so that + ** the accumulators are not populated unless the min()/max() is invoked + ** and indicates that they should be. */ + sqlite3VdbeAddOp2(v, OP_Copy, regAcc, regHit); + } + addrNext = sqlite3VdbeMakeLabel(pParse); + sqlite3ExprIfFalse(pParse, pFilter, addrNext, SQLITE_JUMPIFNULL); + } + if( pF->iOBTab>=0 ){ + /* Instead of invoking AggStep, we must push the arguments that would + ** have been passed to AggStep onto the sorting table. */ + int jj; /* Registered used so far in building the record */ + ExprList *pOBList; /* The ORDER BY clause */ + assert( pList!=0 ); + nArg = pList->nExpr; + assert( nArg>0 ); + assert( pF->pFExpr->pLeft!=0 ); + assert( pF->pFExpr->pLeft->op==TK_ORDER ); + assert( ExprUseXList(pF->pFExpr->pLeft) ); + pOBList = pF->pFExpr->pLeft->x.pList; + assert( pOBList!=0 ); + assert( pOBList->nExpr>0 ); + regAggSz = pOBList->nExpr; + if( !pF->bOBUnique ){ + regAggSz++; /* One register for OP_Sequence */ + } + if( pF->bOBPayload ){ + regAggSz += nArg; + } + if( pF->bUseSubtype ){ + regAggSz += nArg; + } + regAggSz++; /* One extra register to hold result of MakeRecord */ + regAgg = sqlite3GetTempRange(pParse, regAggSz); + regDistinct = regAgg; + sqlite3ExprCodeExprList(pParse, pOBList, regAgg, 0, SQLITE_ECEL_DUP); + jj = pOBList->nExpr; + if( !pF->bOBUnique ){ + sqlite3VdbeAddOp2(v, OP_Sequence, pF->iOBTab, regAgg+jj); + jj++; + } + if( pF->bOBPayload ){ + regDistinct = regAgg+jj; + sqlite3ExprCodeExprList(pParse, pList, regDistinct, 0, SQLITE_ECEL_DUP); + jj += nArg; + } + if( pF->bUseSubtype ){ + int kk; + int regBase = pF->bOBPayload ? regDistinct : regAgg; + for(kk=0; kk<nArg; kk++, jj++){ + sqlite3VdbeAddOp2(v, OP_GetSubtype, regBase+kk, regAgg+jj); + } + } + }else if( pList ){ + nArg = pList->nExpr; + regAgg = sqlite3GetTempRange(pParse, nArg); + regDistinct = regAgg; + sqlite3ExprCodeExprList(pParse, pList, regAgg, 0, SQLITE_ECEL_DUP); + }else{ + nArg = 0; + regAgg = 0; + } + if( pF->iDistinct>=0 && pList ){ + if( addrNext==0 ){ + addrNext = sqlite3VdbeMakeLabel(pParse); + } + pF->iDistinct = codeDistinct(pParse, eDistinctType, + pF->iDistinct, addrNext, pList, regDistinct); + } + if( pF->iOBTab>=0 ){ + /* Insert a new record into the ORDER BY table */ + sqlite3VdbeAddOp3(v, OP_MakeRecord, regAgg, regAggSz-1, + regAgg+regAggSz-1); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pF->iOBTab, regAgg+regAggSz-1, + regAgg, regAggSz-1); + sqlite3ReleaseTempRange(pParse, regAgg, regAggSz); + }else{ + /* Invoke the AggStep function */ + if( pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){ + CollSeq *pColl = 0; + struct ExprList_item *pItem; + int j; + assert( pList!=0 ); /* pList!=0 if pF->pFunc has NEEDCOLL */ + for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){ + pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr); + } + if( !pColl ){ + pColl = pParse->db->pDfltColl; + } + if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem; + sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0, + (char *)pColl, P4_COLLSEQ); + } + sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i)); + sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, (u8)nArg); + sqlite3ReleaseTempRange(pParse, regAgg, nArg); + } + if( addrNext ){ + sqlite3VdbeResolveLabel(v, addrNext); + } + } + if( regHit==0 && pAggInfo->nAccumulator ){ + regHit = regAcc; + } + if( regHit ){ + addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit); VdbeCoverage(v); + } + for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){ + sqlite3ExprCode(pParse, pC->pCExpr, AggInfoColumnReg(pAggInfo,i)); + } + + pAggInfo->directMode = 0; + if( addrHitTest ){ + sqlite3VdbeJumpHereOrPopInst(v, addrHitTest); + } +} + +/* +** Add a single OP_Explain instruction to the VDBE to explain a simple +** count(*) query ("SELECT count(*) FROM pTab"). +*/ +#ifndef SQLITE_OMIT_EXPLAIN +static void explainSimpleCount( + Parse *pParse, /* Parse context */ + Table *pTab, /* Table being queried */ + Index *pIdx /* Index used to optimize scan, or NULL */ +){ + if( pParse->explain==2 ){ + int bCover = (pIdx!=0 && (HasRowid(pTab) || !IsPrimaryKeyIndex(pIdx))); + sqlite3VdbeExplain(pParse, 0, "SCAN %s%s%s", + pTab->zName, + bCover ? " USING COVERING INDEX " : "", + bCover ? pIdx->zName : "" + ); + } +} +#else +# define explainSimpleCount(a,b,c) +#endif + +/* +** sqlite3WalkExpr() callback used by havingToWhere(). +** +** If the node passed to the callback is a TK_AND node, return +** WRC_Continue to tell sqlite3WalkExpr() to iterate through child nodes. +** +** Otherwise, return WRC_Prune. In this case, also check if the +** sub-expression matches the criteria for being moved to the WHERE +** clause. If so, add it to the WHERE clause and replace the sub-expression +** within the HAVING expression with a constant "1". +*/ +static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){ + if( pExpr->op!=TK_AND ){ + Select *pS = pWalker->u.pSelect; + /* This routine is called before the HAVING clause of the current + ** SELECT is analyzed for aggregates. So if pExpr->pAggInfo is set + ** here, it indicates that the expression is a correlated reference to a + ** column from an outer aggregate query, or an aggregate function that + ** belongs to an outer query. Do not move the expression to the WHERE + ** clause in this obscure case, as doing so may corrupt the outer Select + ** statements AggInfo structure. */ + if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy) + && ExprAlwaysFalse(pExpr)==0 + && pExpr->pAggInfo==0 + ){ + sqlite3 *db = pWalker->pParse->db; + Expr *pNew = sqlite3Expr(db, TK_INTEGER, "1"); + if( pNew ){ + Expr *pWhere = pS->pWhere; + SWAP(Expr, *pNew, *pExpr); + pNew = sqlite3ExprAnd(pWalker->pParse, pWhere, pNew); + pS->pWhere = pNew; + pWalker->eCode = 1; + } + } + return WRC_Prune; + } + return WRC_Continue; +} + +/* +** Transfer eligible terms from the HAVING clause of a query, which is +** processed after grouping, to the WHERE clause, which is processed before +** grouping. For example, the query: +** +** SELECT * FROM <tables> WHERE a=? GROUP BY b HAVING b=? AND c=? +** +** can be rewritten as: +** +** SELECT * FROM <tables> WHERE a=? AND b=? GROUP BY b HAVING c=? +** +** A term of the HAVING expression is eligible for transfer if it consists +** entirely of constants and expressions that are also GROUP BY terms that +** use the "BINARY" collation sequence. +*/ +static void havingToWhere(Parse *pParse, Select *p){ + Walker sWalker; + memset(&sWalker, 0, sizeof(sWalker)); + sWalker.pParse = pParse; + sWalker.xExprCallback = havingToWhereExprCb; + sWalker.u.pSelect = p; + sqlite3WalkExpr(&sWalker, p->pHaving); +#if TREETRACE_ENABLED + if( sWalker.eCode && (sqlite3TreeTrace & 0x100)!=0 ){ + TREETRACE(0x100,pParse,p,("Move HAVING terms into WHERE:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif +} + +/* +** Check to see if the pThis entry of pTabList is a self-join of another view. +** Search FROM-clause entries in the range of iFirst..iEnd, including iFirst +** but stopping before iEnd. +** +** If pThis is a self-join, then return the SrcItem for the first other +** instance of that view found. If pThis is not a self-join then return 0. +*/ +static SrcItem *isSelfJoinView( + SrcList *pTabList, /* Search for self-joins in this FROM clause */ + SrcItem *pThis, /* Search for prior reference to this subquery */ + int iFirst, int iEnd /* Range of FROM-clause entries to search. */ +){ + SrcItem *pItem; + assert( pThis->pSelect!=0 ); + if( pThis->pSelect->selFlags & SF_PushDown ) return 0; + while( iFirst<iEnd ){ + Select *pS1; + pItem = &pTabList->a[iFirst++]; + if( pItem->pSelect==0 ) continue; + if( pItem->fg.viaCoroutine ) continue; + if( pItem->zName==0 ) continue; + assert( pItem->pTab!=0 ); + assert( pThis->pTab!=0 ); + if( pItem->pTab->pSchema!=pThis->pTab->pSchema ) continue; + if( sqlite3_stricmp(pItem->zName, pThis->zName)!=0 ) continue; + pS1 = pItem->pSelect; + if( pItem->pTab->pSchema==0 && pThis->pSelect->selId!=pS1->selId ){ + /* The query flattener left two different CTE tables with identical + ** names in the same FROM clause. */ + continue; + } + if( pItem->pSelect->selFlags & SF_PushDown ){ + /* The view was modified by some other optimization such as + ** pushDownWhereTerms() */ + continue; + } + return pItem; + } + return 0; +} + +/* +** Deallocate a single AggInfo object +*/ +static void agginfoFree(sqlite3 *db, void *pArg){ + AggInfo *p = (AggInfo*)pArg; + sqlite3DbFree(db, p->aCol); + sqlite3DbFree(db, p->aFunc); + sqlite3DbFreeNN(db, p); +} + +/* +** Attempt to transform a query of the form +** +** SELECT count(*) FROM (SELECT x FROM t1 UNION ALL SELECT y FROM t2) +** +** Into this: +** +** SELECT (SELECT count(*) FROM t1)+(SELECT count(*) FROM t2) +** +** The transformation only works if all of the following are true: +** +** * The subquery is a UNION ALL of two or more terms +** * The subquery does not have a LIMIT clause +** * There is no WHERE or GROUP BY or HAVING clauses on the subqueries +** * The outer query is a simple count(*) with no WHERE clause or other +** extraneous syntax. +** +** Return TRUE if the optimization is undertaken. +*/ +static int countOfViewOptimization(Parse *pParse, Select *p){ + Select *pSub, *pPrior; + Expr *pExpr; + Expr *pCount; + sqlite3 *db; + if( (p->selFlags & SF_Aggregate)==0 ) return 0; /* This is an aggregate */ + if( p->pEList->nExpr!=1 ) return 0; /* Single result column */ + if( p->pWhere ) return 0; + if( p->pHaving ) return 0; + if( p->pGroupBy ) return 0; + if( p->pOrderBy ) return 0; + pExpr = p->pEList->a[0].pExpr; + if( pExpr->op!=TK_AGG_FUNCTION ) return 0; /* Result is an aggregate */ + assert( ExprUseUToken(pExpr) ); + if( sqlite3_stricmp(pExpr->u.zToken,"count") ) return 0; /* Is count() */ + assert( ExprUseXList(pExpr) ); + if( pExpr->x.pList!=0 ) return 0; /* Must be count(*) */ + if( p->pSrc->nSrc!=1 ) return 0; /* One table in FROM */ + if( ExprHasProperty(pExpr, EP_WinFunc) ) return 0;/* Not a window function */ + pSub = p->pSrc->a[0].pSelect; + if( pSub==0 ) return 0; /* The FROM is a subquery */ + if( pSub->pPrior==0 ) return 0; /* Must be a compound */ + if( pSub->selFlags & SF_CopyCte ) return 0; /* Not a CTE */ + do{ + if( pSub->op!=TK_ALL && pSub->pPrior ) return 0; /* Must be UNION ALL */ + if( pSub->pWhere ) return 0; /* No WHERE clause */ + if( pSub->pLimit ) return 0; /* No LIMIT clause */ + if( pSub->selFlags & SF_Aggregate ) return 0; /* Not an aggregate */ + assert( pSub->pHaving==0 ); /* Due to the previous */ + pSub = pSub->pPrior; /* Repeat over compound */ + }while( pSub ); + + /* If we reach this point then it is OK to perform the transformation */ + + db = pParse->db; + pCount = pExpr; + pExpr = 0; + pSub = p->pSrc->a[0].pSelect; + p->pSrc->a[0].pSelect = 0; + sqlite3SrcListDelete(db, p->pSrc); + p->pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*p->pSrc)); + while( pSub ){ + Expr *pTerm; + pPrior = pSub->pPrior; + pSub->pPrior = 0; + pSub->pNext = 0; + pSub->selFlags |= SF_Aggregate; + pSub->selFlags &= ~SF_Compound; + pSub->nSelectRow = 0; + sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pSub->pEList); + pTerm = pPrior ? sqlite3ExprDup(db, pCount, 0) : pCount; + pSub->pEList = sqlite3ExprListAppend(pParse, 0, pTerm); + pTerm = sqlite3PExpr(pParse, TK_SELECT, 0, 0); + sqlite3PExprAddSelect(pParse, pTerm, pSub); + if( pExpr==0 ){ + pExpr = pTerm; + }else{ + pExpr = sqlite3PExpr(pParse, TK_PLUS, pTerm, pExpr); + } + pSub = pPrior; + } + p->pEList->a[0].pExpr = pExpr; + p->selFlags &= ~SF_Aggregate; + +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x200 ){ + TREETRACE(0x200,pParse,p,("After count-of-view optimization:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + return 1; +} + +/* +** If any term of pSrc, or any SF_NestedFrom sub-query, is not the same +** as pSrcItem but has the same alias as p0, then return true. +** Otherwise return false. +*/ +static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){ + int i; + for(i=0; i<pSrc->nSrc; i++){ + SrcItem *p1 = &pSrc->a[i]; + if( p1==p0 ) continue; + if( p0->pTab==p1->pTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){ + return 1; + } + if( p1->pSelect + && (p1->pSelect->selFlags & SF_NestedFrom)!=0 + && sameSrcAlias(p0, p1->pSelect->pSrc) + ){ + return 1; + } + } + return 0; +} + +/* +** Return TRUE (non-zero) if the i-th entry in the pTabList SrcList can +** be implemented as a co-routine. The i-th entry is guaranteed to be +** a subquery. +** +** The subquery is implemented as a co-routine if all of the following are +** true: +** +** (1) The subquery will likely be implemented in the outer loop of +** the query. This will be the case if any one of the following +** conditions hold: +** (a) The subquery is the only term in the FROM clause +** (b) The subquery is the left-most term and a CROSS JOIN or similar +** requires it to be the outer loop +** (c) All of the following are true: +** (i) The subquery is the left-most subquery in the FROM clause +** (ii) There is nothing that would prevent the subquery from +** being used as the outer loop if the sqlite3WhereBegin() +** routine nominates it to that position. +** (iii) The query is not a UPDATE ... FROM +** (2) The subquery is not a CTE that should be materialized because +** (a) the AS MATERIALIZED keyword is used, or +** (b) the CTE is used multiple times and does not have the +** NOT MATERIALIZED keyword +** (3) The subquery is not part of a left operand for a RIGHT JOIN +** (4) The SQLITE_Coroutine optimization disable flag is not set +** (5) The subquery is not self-joined +*/ +static int fromClauseTermCanBeCoroutine( + Parse *pParse, /* Parsing context */ + SrcList *pTabList, /* FROM clause */ + int i, /* Which term of the FROM clause holds the subquery */ + int selFlags /* Flags on the SELECT statement */ +){ + SrcItem *pItem = &pTabList->a[i]; + if( pItem->fg.isCte ){ + const CteUse *pCteUse = pItem->u2.pCteUse; + if( pCteUse->eM10d==M10d_Yes ) return 0; /* (2a) */ + if( pCteUse->nUse>=2 && pCteUse->eM10d!=M10d_No ) return 0; /* (2b) */ + } + if( pTabList->a[0].fg.jointype & JT_LTORJ ) return 0; /* (3) */ + if( OptimizationDisabled(pParse->db, SQLITE_Coroutines) ) return 0; /* (4) */ + if( isSelfJoinView(pTabList, pItem, i+1, pTabList->nSrc)!=0 ){ + return 0; /* (5) */ + } + if( i==0 ){ + if( pTabList->nSrc==1 ) return 1; /* (1a) */ + if( pTabList->a[1].fg.jointype & JT_CROSS ) return 1; /* (1b) */ + if( selFlags & SF_UpdateFrom ) return 0; /* (1c-iii) */ + return 1; + } + if( selFlags & SF_UpdateFrom ) return 0; /* (1c-iii) */ + while( 1 /*exit-by-break*/ ){ + if( pItem->fg.jointype & (JT_OUTER|JT_CROSS) ) return 0; /* (1c-ii) */ + if( i==0 ) break; + i--; + pItem--; + if( pItem->pSelect!=0 ) return 0; /* (1c-i) */ + } + return 1; +} + +/* +** Generate code for the SELECT statement given in the p argument. +** +** The results are returned according to the SelectDest structure. +** See comments in sqliteInt.h for further information. +** +** This routine returns the number of errors. If any errors are +** encountered, then an appropriate error message is left in +** pParse->zErrMsg. +** +** This routine does NOT free the Select structure passed in. The +** calling function needs to do that. +*/ +int sqlite3Select( + Parse *pParse, /* The parser context */ + Select *p, /* The SELECT statement being coded. */ + SelectDest *pDest /* What to do with the query results */ +){ + int i, j; /* Loop counters */ + WhereInfo *pWInfo; /* Return from sqlite3WhereBegin() */ + Vdbe *v; /* The virtual machine under construction */ + int isAgg; /* True for select lists like "count(*)" */ + ExprList *pEList = 0; /* List of columns to extract. */ + SrcList *pTabList; /* List of tables to select from */ + Expr *pWhere; /* The WHERE clause. May be NULL */ + ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */ + Expr *pHaving; /* The HAVING clause. May be NULL */ + AggInfo *pAggInfo = 0; /* Aggregate information */ + int rc = 1; /* Value to return from this function */ + DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */ + SortCtx sSort; /* Info on how to code the ORDER BY clause */ + int iEnd; /* Address of the end of the query */ + sqlite3 *db; /* The database connection */ + ExprList *pMinMaxOrderBy = 0; /* Added ORDER BY for min/max queries */ + u8 minMaxFlag; /* Flag for min/max queries */ + + db = pParse->db; + assert( pParse==db->pParse ); + v = sqlite3GetVdbe(pParse); + if( p==0 || pParse->nErr ){ + return 1; + } + assert( db->mallocFailed==0 ); + if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1; +#if TREETRACE_ENABLED + TREETRACE(0x1,pParse,p, ("begin processing:\n", pParse->addrExplain)); + if( sqlite3TreeTrace & 0x10000 ){ + if( (sqlite3TreeTrace & 0x10001)==0x10000 ){ + sqlite3TreeViewLine(0, "In sqlite3Select() at %s:%d", + __FILE__, __LINE__); + } + sqlite3ShowSelect(p); + } +#endif + + assert( p->pOrderBy==0 || pDest->eDest!=SRT_DistFifo ); + assert( p->pOrderBy==0 || pDest->eDest!=SRT_Fifo ); + assert( p->pOrderBy==0 || pDest->eDest!=SRT_DistQueue ); + assert( p->pOrderBy==0 || pDest->eDest!=SRT_Queue ); + if( IgnorableDistinct(pDest) ){ + assert(pDest->eDest==SRT_Exists || pDest->eDest==SRT_Union || + pDest->eDest==SRT_Except || pDest->eDest==SRT_Discard || + pDest->eDest==SRT_DistQueue || pDest->eDest==SRT_DistFifo ); + /* All of these destinations are also able to ignore the ORDER BY clause */ + if( p->pOrderBy ){ +#if TREETRACE_ENABLED + TREETRACE(0x800,pParse,p, ("dropping superfluous ORDER BY:\n")); + if( sqlite3TreeTrace & 0x800 ){ + sqlite3TreeViewExprList(0, p->pOrderBy, 0, "ORDERBY"); + } +#endif + sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, + p->pOrderBy); + testcase( pParse->earlyCleanup ); + p->pOrderBy = 0; + } + p->selFlags &= ~SF_Distinct; + p->selFlags |= SF_NoopOrderBy; + } + sqlite3SelectPrep(pParse, p, 0); + if( pParse->nErr ){ + goto select_end; + } + assert( db->mallocFailed==0 ); + assert( p->pEList!=0 ); +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x10 ){ + TREETRACE(0x10,pParse,p, ("after name resolution:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + + /* If the SF_UFSrcCheck flag is set, then this function is being called + ** as part of populating the temp table for an UPDATE...FROM statement. + ** In this case, it is an error if the target object (pSrc->a[0]) name + ** or alias is duplicated within FROM clause (pSrc->a[1..n]). + ** + ** Postgres disallows this case too. The reason is that some other + ** systems handle this case differently, and not all the same way, + ** which is just confusing. To avoid this, we follow PG's lead and + ** disallow it altogether. */ + if( p->selFlags & SF_UFSrcCheck ){ + SrcItem *p0 = &p->pSrc->a[0]; + if( sameSrcAlias(p0, p->pSrc) ){ + sqlite3ErrorMsg(pParse, + "target object/alias may not appear in FROM clause: %s", + p0->zAlias ? p0->zAlias : p0->pTab->zName + ); + goto select_end; + } + + /* Clear the SF_UFSrcCheck flag. The check has already been performed, + ** and leaving this flag set can cause errors if a compound sub-query + ** in p->pSrc is flattened into this query and this function called + ** again as part of compound SELECT processing. */ + p->selFlags &= ~SF_UFSrcCheck; + } + + if( pDest->eDest==SRT_Output ){ + sqlite3GenerateColumnNames(pParse, p); + } + +#ifndef SQLITE_OMIT_WINDOWFUNC + if( sqlite3WindowRewrite(pParse, p) ){ + assert( pParse->nErr ); + goto select_end; + } +#if TREETRACE_ENABLED + if( p->pWin && (sqlite3TreeTrace & 0x40)!=0 ){ + TREETRACE(0x40,pParse,p, ("after window rewrite:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif +#endif /* SQLITE_OMIT_WINDOWFUNC */ + pTabList = p->pSrc; + isAgg = (p->selFlags & SF_Aggregate)!=0; + memset(&sSort, 0, sizeof(sSort)); + sSort.pOrderBy = p->pOrderBy; + + /* Try to do various optimizations (flattening subqueries, and strength + ** reduction of join operators) in the FROM clause up into the main query + */ +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) + for(i=0; !p->pPrior && i<pTabList->nSrc; i++){ + SrcItem *pItem = &pTabList->a[i]; + Select *pSub = pItem->pSelect; + Table *pTab = pItem->pTab; + + /* The expander should have already created transient Table objects + ** even for FROM clause elements such as subqueries that do not correspond + ** to a real table */ + assert( pTab!=0 ); + + /* Try to simplify joins: + ** + ** LEFT JOIN -> JOIN + ** RIGHT JOIN -> JOIN + ** FULL JOIN -> RIGHT JOIN + ** + ** If terms of the i-th table are used in the WHERE clause in such a + ** way that the i-th table cannot be the NULL row of a join, then + ** perform the appropriate simplification. This is called + ** "OUTER JOIN strength reduction" in the SQLite documentation. + */ + if( (pItem->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 + && sqlite3ExprImpliesNonNullRow(p->pWhere, pItem->iCursor, + pItem->fg.jointype & JT_LTORJ) + && OptimizationEnabled(db, SQLITE_SimplifyJoin) + ){ + if( pItem->fg.jointype & JT_LEFT ){ + if( pItem->fg.jointype & JT_RIGHT ){ + TREETRACE(0x1000,pParse,p, + ("FULL-JOIN simplifies to RIGHT-JOIN on term %d\n",i)); + pItem->fg.jointype &= ~JT_LEFT; + }else{ + TREETRACE(0x1000,pParse,p, + ("LEFT-JOIN simplifies to JOIN on term %d\n",i)); + pItem->fg.jointype &= ~(JT_LEFT|JT_OUTER); + unsetJoinExpr(p->pWhere, pItem->iCursor, 0); + } + } + if( pItem->fg.jointype & JT_LTORJ ){ + for(j=i+1; j<pTabList->nSrc; j++){ + SrcItem *pI2 = &pTabList->a[j]; + if( pI2->fg.jointype & JT_RIGHT ){ + if( pI2->fg.jointype & JT_LEFT ){ + TREETRACE(0x1000,pParse,p, + ("FULL-JOIN simplifies to LEFT-JOIN on term %d\n",j)); + pI2->fg.jointype &= ~JT_RIGHT; + }else{ + TREETRACE(0x1000,pParse,p, + ("RIGHT-JOIN simplifies to JOIN on term %d\n",j)); + pI2->fg.jointype &= ~(JT_RIGHT|JT_OUTER); + unsetJoinExpr(p->pWhere, pI2->iCursor, 1); + } + } + } + for(j=pTabList->nSrc-1; j>=0; j--){ + pTabList->a[j].fg.jointype &= ~JT_LTORJ; + if( pTabList->a[j].fg.jointype & JT_RIGHT ) break; + } + } + } + + /* No further action if this term of the FROM clause is not a subquery */ + if( pSub==0 ) continue; + + /* Catch mismatch in the declared columns of a view and the number of + ** columns in the SELECT on the RHS */ + if( pTab->nCol!=pSub->pEList->nExpr ){ + sqlite3ErrorMsg(pParse, "expected %d columns for '%s' but got %d", + pTab->nCol, pTab->zName, pSub->pEList->nExpr); + goto select_end; + } + + /* Do not attempt the usual optimizations (flattening and ORDER BY + ** elimination) on a MATERIALIZED common table expression because + ** a MATERIALIZED common table expression is an optimization fence. + */ + if( pItem->fg.isCte && pItem->u2.pCteUse->eM10d==M10d_Yes ){ + continue; + } + + /* Do not try to flatten an aggregate subquery. + ** + ** Flattening an aggregate subquery is only possible if the outer query + ** is not a join. But if the outer query is not a join, then the subquery + ** will be implemented as a co-routine and there is no advantage to + ** flattening in that case. + */ + if( (pSub->selFlags & SF_Aggregate)!=0 ) continue; + assert( pSub->pGroupBy==0 ); + + /* If a FROM-clause subquery has an ORDER BY clause that is not + ** really doing anything, then delete it now so that it does not + ** interfere with query flattening. See the discussion at + ** https://sqlite.org/forum/forumpost/2d76f2bcf65d256a + ** + ** Beware of these cases where the ORDER BY clause may not be safely + ** omitted: + ** + ** (1) There is also a LIMIT clause + ** (2) The subquery was added to help with window-function + ** processing + ** (3) The subquery is in the FROM clause of an UPDATE + ** (4) The outer query uses an aggregate function other than + ** the built-in count(), min(), or max(). + ** (5) The ORDER BY isn't going to accomplish anything because + ** one of: + ** (a) The outer query has a different ORDER BY clause + ** (b) The subquery is part of a join + ** See forum post 062d576715d277c8 + ** + ** Also retain the ORDER BY if the OmitOrderBy optimization is disabled. + */ + if( pSub->pOrderBy!=0 + && (p->pOrderBy!=0 || pTabList->nSrc>1) /* Condition (5) */ + && pSub->pLimit==0 /* Condition (1) */ + && (pSub->selFlags & SF_OrderByReqd)==0 /* Condition (2) */ + && (p->selFlags & SF_OrderByReqd)==0 /* Condition (3) and (4) */ + && OptimizationEnabled(db, SQLITE_OmitOrderBy) + ){ + TREETRACE(0x800,pParse,p, + ("omit superfluous ORDER BY on %r FROM-clause subquery\n",i+1)); + sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, + pSub->pOrderBy); + pSub->pOrderBy = 0; + } + + /* If the outer query contains a "complex" result set (that is, + ** if the result set of the outer query uses functions or subqueries) + ** and if the subquery contains an ORDER BY clause and if + ** it will be implemented as a co-routine, then do not flatten. This + ** restriction allows SQL constructs like this: + ** + ** SELECT expensive_function(x) + ** FROM (SELECT x FROM tab ORDER BY y LIMIT 10); + ** + ** The expensive_function() is only computed on the 10 rows that + ** are output, rather than every row of the table. + ** + ** The requirement that the outer query have a complex result set + ** means that flattening does occur on simpler SQL constraints without + ** the expensive_function() like: + ** + ** SELECT x FROM (SELECT x FROM tab ORDER BY y LIMIT 10); + */ + if( pSub->pOrderBy!=0 + && i==0 + && (p->selFlags & SF_ComplexResult)!=0 + && (pTabList->nSrc==1 + || (pTabList->a[1].fg.jointype&(JT_OUTER|JT_CROSS))!=0) + ){ + continue; + } + + if( flattenSubquery(pParse, p, i, isAgg) ){ + if( pParse->nErr ) goto select_end; + /* This subquery can be absorbed into its parent. */ + i = -1; + } + pTabList = p->pSrc; + if( db->mallocFailed ) goto select_end; + if( !IgnorableOrderby(pDest) ){ + sSort.pOrderBy = p->pOrderBy; + } + } +#endif + +#ifndef SQLITE_OMIT_COMPOUND_SELECT + /* Handle compound SELECT statements using the separate multiSelect() + ** procedure. + */ + if( p->pPrior ){ + rc = multiSelect(pParse, p, pDest); +#if TREETRACE_ENABLED + TREETRACE(0x400,pParse,p,("end compound-select processing\n")); + if( (sqlite3TreeTrace & 0x400)!=0 && ExplainQueryPlanParent(pParse)==0 ){ + sqlite3TreeViewSelect(0, p, 0); + } +#endif + if( p->pNext==0 ) ExplainQueryPlanPop(pParse); + return rc; + } +#endif + + /* Do the WHERE-clause constant propagation optimization if this is + ** a join. No need to speed time on this operation for non-join queries + ** as the equivalent optimization will be handled by query planner in + ** sqlite3WhereBegin(). + */ + if( p->pWhere!=0 + && p->pWhere->op==TK_AND + && OptimizationEnabled(db, SQLITE_PropagateConst) + && propagateConstants(pParse, p) + ){ +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x2000 ){ + TREETRACE(0x2000,pParse,p,("After constant propagation:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + }else{ + TREETRACE(0x2000,pParse,p,("Constant propagation not helpful\n")); + } + + if( OptimizationEnabled(db, SQLITE_QueryFlattener|SQLITE_CountOfView) + && countOfViewOptimization(pParse, p) + ){ + if( db->mallocFailed ) goto select_end; + pTabList = p->pSrc; + } + + /* For each term in the FROM clause, do two things: + ** (1) Authorized unreferenced tables + ** (2) Generate code for all sub-queries + */ + for(i=0; i<pTabList->nSrc; i++){ + SrcItem *pItem = &pTabList->a[i]; + SrcItem *pPrior; + SelectDest dest; + Select *pSub; +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) + const char *zSavedAuthContext; +#endif + + /* Issue SQLITE_READ authorizations with a fake column name for any + ** tables that are referenced but from which no values are extracted. + ** Examples of where these kinds of null SQLITE_READ authorizations + ** would occur: + ** + ** SELECT count(*) FROM t1; -- SQLITE_READ t1."" + ** SELECT t1.* FROM t1, t2; -- SQLITE_READ t2."" + ** + ** The fake column name is an empty string. It is possible for a table to + ** have a column named by the empty string, in which case there is no way to + ** distinguish between an unreferenced table and an actual reference to the + ** "" column. The original design was for the fake column name to be a NULL, + ** which would be unambiguous. But legacy authorization callbacks might + ** assume the column name is non-NULL and segfault. The use of an empty + ** string for the fake column name seems safer. + */ + if( pItem->colUsed==0 && pItem->zName!=0 ){ + sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", pItem->zDatabase); + } + +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) + /* Generate code for all sub-queries in the FROM clause + */ + pSub = pItem->pSelect; + if( pSub==0 ) continue; + + /* The code for a subquery should only be generated once. */ + assert( pItem->addrFillSub==0 ); + + /* Increment Parse.nHeight by the height of the largest expression + ** tree referred to by this, the parent select. The child select + ** may contain expression trees of at most + ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit + ** more conservative than necessary, but much easier than enforcing + ** an exact limit. + */ + pParse->nHeight += sqlite3SelectExprHeight(p); + + /* Make copies of constant WHERE-clause terms in the outer query down + ** inside the subquery. This can help the subquery to run more efficiently. + */ + if( OptimizationEnabled(db, SQLITE_PushDown) + && (pItem->fg.isCte==0 + || (pItem->u2.pCteUse->eM10d!=M10d_Yes && pItem->u2.pCteUse->nUse<2)) + && pushDownWhereTerms(pParse, pSub, p->pWhere, pTabList, i) + ){ +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x4000 ){ + TREETRACE(0x4000,pParse,p, + ("After WHERE-clause push-down into subquery %d:\n", pSub->selId)); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + assert( pItem->pSelect && (pItem->pSelect->selFlags & SF_PushDown)!=0 ); + }else{ + TREETRACE(0x4000,pParse,p,("Push-down not possible\n")); + } + + /* Convert unused result columns of the subquery into simple NULL + ** expressions, to avoid unneeded searching and computation. + */ + if( OptimizationEnabled(db, SQLITE_NullUnusedCols) + && disableUnusedSubqueryResultColumns(pItem) + ){ +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x4000 ){ + TREETRACE(0x4000,pParse,p, + ("Change unused result columns to NULL for subquery %d:\n", + pSub->selId)); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + } + + zSavedAuthContext = pParse->zAuthContext; + pParse->zAuthContext = pItem->zName; + + /* Generate code to implement the subquery + */ + if( fromClauseTermCanBeCoroutine(pParse, pTabList, i, p->selFlags) ){ + /* Implement a co-routine that will return a single row of the result + ** set on each invocation. + */ + int addrTop = sqlite3VdbeCurrentAddr(v)+1; + + pItem->regReturn = ++pParse->nMem; + sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->regReturn, 0, addrTop); + VdbeComment((v, "%!S", pItem)); + pItem->addrFillSub = addrTop; + sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn); + ExplainQueryPlan((pParse, 1, "CO-ROUTINE %!S", pItem)); + sqlite3Select(pParse, pSub, &dest); + pItem->pTab->nRowLogEst = pSub->nSelectRow; + pItem->fg.viaCoroutine = 1; + pItem->regResult = dest.iSdst; + sqlite3VdbeEndCoroutine(v, pItem->regReturn); + sqlite3VdbeJumpHere(v, addrTop-1); + sqlite3ClearTempRegCache(pParse); + }else if( pItem->fg.isCte && pItem->u2.pCteUse->addrM9e>0 ){ + /* This is a CTE for which materialization code has already been + ** generated. Invoke the subroutine to compute the materialization, + ** the make the pItem->iCursor be a copy of the ephemeral table that + ** holds the result of the materialization. */ + CteUse *pCteUse = pItem->u2.pCteUse; + sqlite3VdbeAddOp2(v, OP_Gosub, pCteUse->regRtn, pCteUse->addrM9e); + if( pItem->iCursor!=pCteUse->iCur ){ + sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pCteUse->iCur); + VdbeComment((v, "%!S", pItem)); + } + pSub->nSelectRow = pCteUse->nRowEst; + }else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){ + /* This view has already been materialized by a prior entry in + ** this same FROM clause. Reuse it. */ + if( pPrior->addrFillSub ){ + sqlite3VdbeAddOp2(v, OP_Gosub, pPrior->regReturn, pPrior->addrFillSub); + } + sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pPrior->iCursor); + pSub->nSelectRow = pPrior->pSelect->nSelectRow; + }else{ + /* Materialize the view. If the view is not correlated, generate a + ** subroutine to do the materialization so that subsequent uses of + ** the same view can reuse the materialization. */ + int topAddr; + int onceAddr = 0; +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + int addrExplain; +#endif + + pItem->regReturn = ++pParse->nMem; + topAddr = sqlite3VdbeAddOp0(v, OP_Goto); + pItem->addrFillSub = topAddr+1; + pItem->fg.isMaterialized = 1; + if( pItem->fg.isCorrelated==0 ){ + /* If the subquery is not correlated and if we are not inside of + ** a trigger, then we only need to compute the value of the subquery + ** once. */ + onceAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v); + VdbeComment((v, "materialize %!S", pItem)); + }else{ + VdbeNoopComment((v, "materialize %!S", pItem)); + } + sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor); + + ExplainQueryPlan2(addrExplain, (pParse, 1, "MATERIALIZE %!S", pItem)); + sqlite3Select(pParse, pSub, &dest); + pItem->pTab->nRowLogEst = pSub->nSelectRow; + if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr); + sqlite3VdbeAddOp2(v, OP_Return, pItem->regReturn, topAddr+1); + VdbeComment((v, "end %!S", pItem)); + sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1); + sqlite3VdbeJumpHere(v, topAddr); + sqlite3ClearTempRegCache(pParse); + if( pItem->fg.isCte && pItem->fg.isCorrelated==0 ){ + CteUse *pCteUse = pItem->u2.pCteUse; + pCteUse->addrM9e = pItem->addrFillSub; + pCteUse->regRtn = pItem->regReturn; + pCteUse->iCur = pItem->iCursor; + pCteUse->nRowEst = pSub->nSelectRow; + } + } + if( db->mallocFailed ) goto select_end; + pParse->nHeight -= sqlite3SelectExprHeight(p); + pParse->zAuthContext = zSavedAuthContext; +#endif + } + + /* Various elements of the SELECT copied into local variables for + ** convenience */ + pEList = p->pEList; + pWhere = p->pWhere; + pGroupBy = p->pGroupBy; + pHaving = p->pHaving; + sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0; + +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x8000 ){ + TREETRACE(0x8000,pParse,p,("After all FROM-clause analysis:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + + /* If the query is DISTINCT with an ORDER BY but is not an aggregate, and + ** if the select-list is the same as the ORDER BY list, then this query + ** can be rewritten as a GROUP BY. In other words, this: + ** + ** SELECT DISTINCT xyz FROM ... ORDER BY xyz + ** + ** is transformed to: + ** + ** SELECT xyz FROM ... GROUP BY xyz ORDER BY xyz + ** + ** The second form is preferred as a single index (or temp-table) may be + ** used for both the ORDER BY and DISTINCT processing. As originally + ** written the query must use a temp-table for at least one of the ORDER + ** BY and DISTINCT, and an index or separate temp-table for the other. + */ + if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct + && sqlite3ExprListCompare(sSort.pOrderBy, pEList, -1)==0 +#ifndef SQLITE_OMIT_WINDOWFUNC + && p->pWin==0 +#endif + ){ + p->selFlags &= ~SF_Distinct; + pGroupBy = p->pGroupBy = sqlite3ExprListDup(db, pEList, 0); + p->selFlags |= SF_Aggregate; + /* Notice that even thought SF_Distinct has been cleared from p->selFlags, + ** the sDistinct.isTnct is still set. Hence, isTnct represents the + ** original setting of the SF_Distinct flag, not the current setting */ + assert( sDistinct.isTnct ); + sDistinct.isTnct = 2; + +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x20000 ){ + TREETRACE(0x20000,pParse,p,("Transform DISTINCT into GROUP BY:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + } + + /* If there is an ORDER BY clause, then create an ephemeral index to + ** do the sorting. But this sorting ephemeral index might end up + ** being unused if the data can be extracted in pre-sorted order. + ** If that is the case, then the OP_OpenEphemeral instruction will be + ** changed to an OP_Noop once we figure out that the sorting index is + ** not needed. The sSort.addrSortIndex variable is used to facilitate + ** that change. + */ + if( sSort.pOrderBy ){ + KeyInfo *pKeyInfo; + pKeyInfo = sqlite3KeyInfoFromExprList( + pParse, sSort.pOrderBy, 0, pEList->nExpr); + sSort.iECursor = pParse->nTab++; + sSort.addrSortIndex = + sqlite3VdbeAddOp4(v, OP_OpenEphemeral, + sSort.iECursor, sSort.pOrderBy->nExpr+1+pEList->nExpr, 0, + (char*)pKeyInfo, P4_KEYINFO + ); + }else{ + sSort.addrSortIndex = -1; + } + + /* If the output is destined for a temporary table, open that table. + */ + if( pDest->eDest==SRT_EphemTab ){ + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr); + if( p->selFlags & SF_NestedFrom ){ + /* Delete or NULL-out result columns that will never be used */ + int ii; + for(ii=pEList->nExpr-1; ii>0 && pEList->a[ii].fg.bUsed==0; ii--){ + sqlite3ExprDelete(db, pEList->a[ii].pExpr); + sqlite3DbFree(db, pEList->a[ii].zEName); + pEList->nExpr--; + } + for(ii=0; ii<pEList->nExpr; ii++){ + if( pEList->a[ii].fg.bUsed==0 ) pEList->a[ii].pExpr->op = TK_NULL; + } + } + } + + /* Set the limiter. + */ + iEnd = sqlite3VdbeMakeLabel(pParse); + if( (p->selFlags & SF_FixedLimit)==0 ){ + p->nSelectRow = 320; /* 4 billion rows */ + } + if( p->pLimit ) computeLimitRegisters(pParse, p, iEnd); + if( p->iLimit==0 && sSort.addrSortIndex>=0 ){ + sqlite3VdbeChangeOpcode(v, sSort.addrSortIndex, OP_SorterOpen); + sSort.sortFlags |= SORTFLAG_UseSorter; + } + + /* Open an ephemeral index to use for the distinct set. + */ + if( p->selFlags & SF_Distinct ){ + sDistinct.tabTnct = pParse->nTab++; + sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, + sDistinct.tabTnct, 0, 0, + (char*)sqlite3KeyInfoFromExprList(pParse, p->pEList,0,0), + P4_KEYINFO); + sqlite3VdbeChangeP5(v, BTREE_UNORDERED); + sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED; + }else{ + sDistinct.eTnctType = WHERE_DISTINCT_NOOP; + } + + if( !isAgg && pGroupBy==0 ){ + /* No aggregate functions and no GROUP BY clause */ + u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0) + | (p->selFlags & SF_FixedLimit); +#ifndef SQLITE_OMIT_WINDOWFUNC + Window *pWin = p->pWin; /* Main window object (or NULL) */ + if( pWin ){ + sqlite3WindowCodeInit(pParse, p); + } +#endif + assert( WHERE_USE_LIMIT==SF_FixedLimit ); + + + /* Begin the database scan. */ + TREETRACE(0x2,pParse,p,("WhereBegin\n")); + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, sSort.pOrderBy, + p->pEList, p, wctrlFlags, p->nSelectRow); + if( pWInfo==0 ) goto select_end; + if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){ + p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo); + } + if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){ + sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo); + } + if( sSort.pOrderBy ){ + sSort.nOBSat = sqlite3WhereIsOrdered(pWInfo); + sSort.labelOBLopt = sqlite3WhereOrderByLimitOptLabel(pWInfo); + if( sSort.nOBSat==sSort.pOrderBy->nExpr ){ + sSort.pOrderBy = 0; + } + } + TREETRACE(0x2,pParse,p,("WhereBegin returns\n")); + + /* If sorting index that was created by a prior OP_OpenEphemeral + ** instruction ended up not being needed, then change the OP_OpenEphemeral + ** into an OP_Noop. + */ + if( sSort.addrSortIndex>=0 && sSort.pOrderBy==0 ){ + sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex); + } + + assert( p->pEList==pEList ); +#ifndef SQLITE_OMIT_WINDOWFUNC + if( pWin ){ + int addrGosub = sqlite3VdbeMakeLabel(pParse); + int iCont = sqlite3VdbeMakeLabel(pParse); + int iBreak = sqlite3VdbeMakeLabel(pParse); + int regGosub = ++pParse->nMem; + + sqlite3WindowCodeStep(pParse, p, pWInfo, regGosub, addrGosub); + + sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak); + sqlite3VdbeResolveLabel(v, addrGosub); + VdbeNoopComment((v, "inner-loop subroutine")); + sSort.labelOBLopt = 0; + selectInnerLoop(pParse, p, -1, &sSort, &sDistinct, pDest, iCont, iBreak); + sqlite3VdbeResolveLabel(v, iCont); + sqlite3VdbeAddOp1(v, OP_Return, regGosub); + VdbeComment((v, "end inner-loop subroutine")); + sqlite3VdbeResolveLabel(v, iBreak); + }else +#endif /* SQLITE_OMIT_WINDOWFUNC */ + { + /* Use the standard inner loop. */ + selectInnerLoop(pParse, p, -1, &sSort, &sDistinct, pDest, + sqlite3WhereContinueLabel(pWInfo), + sqlite3WhereBreakLabel(pWInfo)); + + /* End the database scan loop. + */ + TREETRACE(0x2,pParse,p,("WhereEnd\n")); + sqlite3WhereEnd(pWInfo); + } + }else{ + /* This case when there exist aggregate functions or a GROUP BY clause + ** or both */ + NameContext sNC; /* Name context for processing aggregate information */ + int iAMem; /* First Mem address for storing current GROUP BY */ + int iBMem; /* First Mem address for previous GROUP BY */ + int iUseFlag; /* Mem address holding flag indicating that at least + ** one row of the input to the aggregator has been + ** processed */ + int iAbortFlag; /* Mem address which causes query abort if positive */ + int groupBySort; /* Rows come from source in GROUP BY order */ + int addrEnd; /* End of processing for this SELECT */ + int sortPTab = 0; /* Pseudotable used to decode sorting results */ + int sortOut = 0; /* Output register from the sorter */ + int orderByGrp = 0; /* True if the GROUP BY and ORDER BY are the same */ + + /* Remove any and all aliases between the result set and the + ** GROUP BY clause. + */ + if( pGroupBy ){ + int k; /* Loop counter */ + struct ExprList_item *pItem; /* For looping over expression in a list */ + + for(k=p->pEList->nExpr, pItem=p->pEList->a; k>0; k--, pItem++){ + pItem->u.x.iAlias = 0; + } + for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){ + pItem->u.x.iAlias = 0; + } + assert( 66==sqlite3LogEst(100) ); + if( p->nSelectRow>66 ) p->nSelectRow = 66; + + /* If there is both a GROUP BY and an ORDER BY clause and they are + ** identical, then it may be possible to disable the ORDER BY clause + ** on the grounds that the GROUP BY will cause elements to come out + ** in the correct order. It also may not - the GROUP BY might use a + ** database index that causes rows to be grouped together as required + ** but not actually sorted. Either way, record the fact that the + ** ORDER BY and GROUP BY clauses are the same by setting the orderByGrp + ** variable. */ + if( sSort.pOrderBy && pGroupBy->nExpr==sSort.pOrderBy->nExpr ){ + int ii; + /* The GROUP BY processing doesn't care whether rows are delivered in + ** ASC or DESC order - only that each group is returned contiguously. + ** So set the ASC/DESC flags in the GROUP BY to match those in the + ** ORDER BY to maximize the chances of rows being delivered in an + ** order that makes the ORDER BY redundant. */ + for(ii=0; ii<pGroupBy->nExpr; ii++){ + u8 sortFlags; + sortFlags = sSort.pOrderBy->a[ii].fg.sortFlags & KEYINFO_ORDER_DESC; + pGroupBy->a[ii].fg.sortFlags = sortFlags; + } + if( sqlite3ExprListCompare(pGroupBy, sSort.pOrderBy, -1)==0 ){ + orderByGrp = 1; + } + } + }else{ + assert( 0==sqlite3LogEst(1) ); + p->nSelectRow = 0; + } + + /* Create a label to jump to when we want to abort the query */ + addrEnd = sqlite3VdbeMakeLabel(pParse); + + /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in + ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the + ** SELECT statement. + */ + pAggInfo = sqlite3DbMallocZero(db, sizeof(*pAggInfo) ); + if( pAggInfo ){ + sqlite3ParserAddCleanup(pParse, agginfoFree, pAggInfo); + testcase( pParse->earlyCleanup ); + } + if( db->mallocFailed ){ + goto select_end; + } + pAggInfo->selId = p->selId; +#ifdef SQLITE_DEBUG + pAggInfo->pSelect = p; +#endif + memset(&sNC, 0, sizeof(sNC)); + sNC.pParse = pParse; + sNC.pSrcList = pTabList; + sNC.uNC.pAggInfo = pAggInfo; + VVA_ONLY( sNC.ncFlags = NC_UAggInfo; ) + pAggInfo->nSortingColumn = pGroupBy ? pGroupBy->nExpr : 0; + pAggInfo->pGroupBy = pGroupBy; + sqlite3ExprAnalyzeAggList(&sNC, pEList); + sqlite3ExprAnalyzeAggList(&sNC, sSort.pOrderBy); + if( pHaving ){ + if( pGroupBy ){ + assert( pWhere==p->pWhere ); + assert( pHaving==p->pHaving ); + assert( pGroupBy==p->pGroupBy ); + havingToWhere(pParse, p); + pWhere = p->pWhere; + } + sqlite3ExprAnalyzeAggregates(&sNC, pHaving); + } + pAggInfo->nAccumulator = pAggInfo->nColumn; + if( p->pGroupBy==0 && p->pHaving==0 && pAggInfo->nFunc==1 ){ + minMaxFlag = minMaxQuery(db, pAggInfo->aFunc[0].pFExpr, &pMinMaxOrderBy); + }else{ + minMaxFlag = WHERE_ORDERBY_NORMAL; + } + analyzeAggFuncArgs(pAggInfo, &sNC); + if( db->mallocFailed ) goto select_end; +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x20 ){ + TREETRACE(0x20,pParse,p,("After aggregate analysis %p:\n", pAggInfo)); + sqlite3TreeViewSelect(0, p, 0); + if( minMaxFlag ){ + sqlite3DebugPrintf("MIN/MAX Optimization (0x%02x) adds:\n", minMaxFlag); + sqlite3TreeViewExprList(0, pMinMaxOrderBy, 0, "ORDERBY"); + } + printAggInfo(pAggInfo); + } +#endif + + + /* Processing for aggregates with GROUP BY is very different and + ** much more complex than aggregates without a GROUP BY. + */ + if( pGroupBy ){ + KeyInfo *pKeyInfo; /* Keying information for the group by clause */ + int addr1; /* A-vs-B comparison jump */ + int addrOutputRow; /* Start of subroutine that outputs a result row */ + int regOutputRow; /* Return address register for output subroutine */ + int addrSetAbort; /* Set the abort flag and return */ + int addrTopOfLoop; /* Top of the input loop */ + int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */ + int addrReset; /* Subroutine for resetting the accumulator */ + int regReset; /* Return address register for reset subroutine */ + ExprList *pDistinct = 0; + u16 distFlag = 0; + int eDist = WHERE_DISTINCT_NOOP; + + if( pAggInfo->nFunc==1 + && pAggInfo->aFunc[0].iDistinct>=0 + && ALWAYS(pAggInfo->aFunc[0].pFExpr!=0) + && ALWAYS(ExprUseXList(pAggInfo->aFunc[0].pFExpr)) + && pAggInfo->aFunc[0].pFExpr->x.pList!=0 + ){ + Expr *pExpr = pAggInfo->aFunc[0].pFExpr->x.pList->a[0].pExpr; + pExpr = sqlite3ExprDup(db, pExpr, 0); + pDistinct = sqlite3ExprListDup(db, pGroupBy, 0); + pDistinct = sqlite3ExprListAppend(pParse, pDistinct, pExpr); + distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0; + } + + /* If there is a GROUP BY clause we might need a sorting index to + ** implement it. Allocate that sorting index now. If it turns out + ** that we do not need it after all, the OP_SorterOpen instruction + ** will be converted into a Noop. + */ + pAggInfo->sortingIdx = pParse->nTab++; + pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pGroupBy, + 0, pAggInfo->nColumn); + addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen, + pAggInfo->sortingIdx, pAggInfo->nSortingColumn, + 0, (char*)pKeyInfo, P4_KEYINFO); + + /* Initialize memory locations used by GROUP BY aggregate processing + */ + iUseFlag = ++pParse->nMem; + iAbortFlag = ++pParse->nMem; + regOutputRow = ++pParse->nMem; + addrOutputRow = sqlite3VdbeMakeLabel(pParse); + regReset = ++pParse->nMem; + addrReset = sqlite3VdbeMakeLabel(pParse); + iAMem = pParse->nMem + 1; + pParse->nMem += pGroupBy->nExpr; + iBMem = pParse->nMem + 1; + pParse->nMem += pGroupBy->nExpr; + sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag); + VdbeComment((v, "clear abort flag")); + sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1); + + /* Begin a loop that will extract all source rows in GROUP BY order. + ** This might involve two separate loops with an OP_Sort in between, or + ** it might be a single loop that uses an index to extract information + ** in the right order to begin with. + */ + sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset); + TREETRACE(0x2,pParse,p,("WhereBegin\n")); + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, pDistinct, + p, (sDistinct.isTnct==2 ? WHERE_DISTINCTBY : WHERE_GROUPBY) + | (orderByGrp ? WHERE_SORTBYGROUP : 0) | distFlag, 0 + ); + if( pWInfo==0 ){ + sqlite3ExprListDelete(db, pDistinct); + goto select_end; + } + if( pParse->pIdxEpr ){ + optimizeAggregateUseOfIndexedExpr(pParse, p, pAggInfo, &sNC); + } + assignAggregateRegisters(pParse, pAggInfo); + eDist = sqlite3WhereIsDistinct(pWInfo); + TREETRACE(0x2,pParse,p,("WhereBegin returns\n")); + if( sqlite3WhereIsOrdered(pWInfo)==pGroupBy->nExpr ){ + /* The optimizer is able to deliver rows in group by order so + ** we do not have to sort. The OP_OpenEphemeral table will be + ** cancelled later because we still need to use the pKeyInfo + */ + groupBySort = 0; + }else{ + /* Rows are coming out in undetermined order. We have to push + ** each row into a sorting index, terminate the first loop, + ** then loop over the sorting index in order to get the output + ** in sorted order + */ + int regBase; + int regRecord; + int nCol; + int nGroupBy; + +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + int addrExp; /* Address of OP_Explain instruction */ +#endif + ExplainQueryPlan2(addrExp, (pParse, 0, "USE TEMP B-TREE FOR %s", + (sDistinct.isTnct && (p->selFlags&SF_Distinct)==0) ? + "DISTINCT" : "GROUP BY" + )); + + groupBySort = 1; + nGroupBy = pGroupBy->nExpr; + nCol = nGroupBy; + j = nGroupBy; + for(i=0; i<pAggInfo->nColumn; i++){ + if( pAggInfo->aCol[i].iSorterColumn>=j ){ + nCol++; + j++; + } + } + regBase = sqlite3GetTempRange(pParse, nCol); + sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0, 0); + j = nGroupBy; + pAggInfo->directMode = 1; + for(i=0; i<pAggInfo->nColumn; i++){ + struct AggInfo_col *pCol = &pAggInfo->aCol[i]; + if( pCol->iSorterColumn>=j ){ + sqlite3ExprCode(pParse, pCol->pCExpr, j + regBase); + j++; + } + } + pAggInfo->directMode = 0; + regRecord = sqlite3GetTempReg(pParse); + sqlite3VdbeScanStatusCounters(v, addrExp, 0, sqlite3VdbeCurrentAddr(v)); + sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord); + sqlite3VdbeAddOp2(v, OP_SorterInsert, pAggInfo->sortingIdx, regRecord); + sqlite3VdbeScanStatusRange(v, addrExp, sqlite3VdbeCurrentAddr(v)-2, -1); + sqlite3ReleaseTempReg(pParse, regRecord); + sqlite3ReleaseTempRange(pParse, regBase, nCol); + TREETRACE(0x2,pParse,p,("WhereEnd\n")); + sqlite3WhereEnd(pWInfo); + pAggInfo->sortingIdxPTab = sortPTab = pParse->nTab++; + sortOut = sqlite3GetTempReg(pParse); + sqlite3VdbeScanStatusCounters(v, addrExp, sqlite3VdbeCurrentAddr(v), 0); + sqlite3VdbeAddOp3(v, OP_OpenPseudo, sortPTab, sortOut, nCol); + sqlite3VdbeAddOp2(v, OP_SorterSort, pAggInfo->sortingIdx, addrEnd); + VdbeComment((v, "GROUP BY sort")); VdbeCoverage(v); + pAggInfo->useSortingIdx = 1; + sqlite3VdbeScanStatusRange(v, addrExp, -1, sortPTab); + sqlite3VdbeScanStatusRange(v, addrExp, -1, pAggInfo->sortingIdx); + } + + /* If there are entries in pAgggInfo->aFunc[] that contain subexpressions + ** that are indexed (and that were previously identified and tagged + ** in optimizeAggregateUseOfIndexedExpr()) then those subexpressions + ** must now be converted into a TK_AGG_COLUMN node so that the value + ** is correctly pulled from the index rather than being recomputed. */ + if( pParse->pIdxEpr ){ + aggregateConvertIndexedExprRefToColumn(pAggInfo); +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x20 ){ + TREETRACE(0x20, pParse, p, + ("AggInfo function expressions converted to reference index\n")); + sqlite3TreeViewSelect(0, p, 0); + printAggInfo(pAggInfo); + } +#endif + } + + /* If the index or temporary table used by the GROUP BY sort + ** will naturally deliver rows in the order required by the ORDER BY + ** clause, cancel the ephemeral table open coded earlier. + ** + ** This is an optimization - the correct answer should result regardless. + ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER to + ** disable this optimization for testing purposes. */ + if( orderByGrp && OptimizationEnabled(db, SQLITE_GroupByOrder) + && (groupBySort || sqlite3WhereIsSorted(pWInfo)) + ){ + sSort.pOrderBy = 0; + sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex); + } + + /* Evaluate the current GROUP BY terms and store in b0, b1, b2... + ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth) + ** Then compare the current GROUP BY terms against the GROUP BY terms + ** from the previous row currently stored in a0, a1, a2... + */ + addrTopOfLoop = sqlite3VdbeCurrentAddr(v); + if( groupBySort ){ + sqlite3VdbeAddOp3(v, OP_SorterData, pAggInfo->sortingIdx, + sortOut, sortPTab); + } + for(j=0; j<pGroupBy->nExpr; j++){ + if( groupBySort ){ + sqlite3VdbeAddOp3(v, OP_Column, sortPTab, j, iBMem+j); + }else{ + pAggInfo->directMode = 1; + sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j); + } + } + sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr, + (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO); + addr1 = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp3(v, OP_Jump, addr1+1, 0, addr1+1); VdbeCoverage(v); + + /* Generate code that runs whenever the GROUP BY changes. + ** Changes in the GROUP BY are detected by the previous code + ** block. If there were no changes, this block is skipped. + ** + ** This code copies current group by terms in b0,b1,b2,... + ** over to a0,a1,a2. It then calls the output subroutine + ** and resets the aggregate accumulator registers in preparation + ** for the next GROUP BY batch. + */ + sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr); + sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow); + VdbeComment((v, "output one row")); + sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd); VdbeCoverage(v); + VdbeComment((v, "check abort flag")); + sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset); + VdbeComment((v, "reset accumulator")); + + /* Update the aggregate accumulators based on the content of + ** the current row + */ + sqlite3VdbeJumpHere(v, addr1); + updateAccumulator(pParse, iUseFlag, pAggInfo, eDist); + sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag); + VdbeComment((v, "indicate data in accumulator")); + + /* End of the loop + */ + if( groupBySort ){ + sqlite3VdbeAddOp2(v, OP_SorterNext, pAggInfo->sortingIdx,addrTopOfLoop); + VdbeCoverage(v); + }else{ + TREETRACE(0x2,pParse,p,("WhereEnd\n")); + sqlite3WhereEnd(pWInfo); + sqlite3VdbeChangeToNoop(v, addrSortingIdx); + } + sqlite3ExprListDelete(db, pDistinct); + + /* Output the final row of result + */ + sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow); + VdbeComment((v, "output final row")); + + /* Jump over the subroutines + */ + sqlite3VdbeGoto(v, addrEnd); + + /* Generate a subroutine that outputs a single row of the result + ** set. This subroutine first looks at the iUseFlag. If iUseFlag + ** is less than or equal to zero, the subroutine is a no-op. If + ** the processing calls for the query to abort, this subroutine + ** increments the iAbortFlag memory location before returning in + ** order to signal the caller to abort. + */ + addrSetAbort = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag); + VdbeComment((v, "set abort flag")); + sqlite3VdbeAddOp1(v, OP_Return, regOutputRow); + sqlite3VdbeResolveLabel(v, addrOutputRow); + addrOutputRow = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2); + VdbeCoverage(v); + VdbeComment((v, "Groupby result generator entry point")); + sqlite3VdbeAddOp1(v, OP_Return, regOutputRow); + finalizeAggFunctions(pParse, pAggInfo); + sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL); + selectInnerLoop(pParse, p, -1, &sSort, + &sDistinct, pDest, + addrOutputRow+1, addrSetAbort); + sqlite3VdbeAddOp1(v, OP_Return, regOutputRow); + VdbeComment((v, "end groupby result generator")); + + /* Generate a subroutine that will reset the group-by accumulator + */ + sqlite3VdbeResolveLabel(v, addrReset); + resetAccumulator(pParse, pAggInfo); + sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag); + VdbeComment((v, "indicate accumulator empty")); + sqlite3VdbeAddOp1(v, OP_Return, regReset); + + if( distFlag!=0 && eDist!=WHERE_DISTINCT_NOOP ){ + struct AggInfo_func *pF = &pAggInfo->aFunc[0]; + fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr); + } + } /* endif pGroupBy. Begin aggregate queries without GROUP BY: */ + else { + Table *pTab; + if( (pTab = isSimpleCount(p, pAggInfo))!=0 ){ + /* If isSimpleCount() returns a pointer to a Table structure, then + ** the SQL statement is of the form: + ** + ** SELECT count(*) FROM <tbl> + ** + ** where the Table structure returned represents table <tbl>. + ** + ** This statement is so common that it is optimized specially. The + ** OP_Count instruction is executed either on the intkey table that + ** contains the data for table <tbl> or on one of its indexes. It + ** is better to execute the op on an index, as indexes are almost + ** always spread across less pages than their corresponding tables. + */ + const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema); + const int iCsr = pParse->nTab++; /* Cursor to scan b-tree */ + Index *pIdx; /* Iterator variable */ + KeyInfo *pKeyInfo = 0; /* Keyinfo for scanned index */ + Index *pBest = 0; /* Best index found so far */ + Pgno iRoot = pTab->tnum; /* Root page of scanned b-tree */ + + sqlite3CodeVerifySchema(pParse, iDb); + sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName); + + /* Search for the index that has the lowest scan cost. + ** + ** (2011-04-15) Do not do a full scan of an unordered index. + ** + ** (2013-10-03) Do not count the entries in a partial index. + ** + ** In practice the KeyInfo structure will not be used. It is only + ** passed to keep OP_OpenRead happy. + */ + if( !HasRowid(pTab) ) pBest = sqlite3PrimaryKeyIndex(pTab); + if( !p->pSrc->a[0].fg.notIndexed ){ + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ + if( pIdx->bUnordered==0 + && pIdx->szIdxRow<pTab->szTabRow + && pIdx->pPartIdxWhere==0 + && (!pBest || pIdx->szIdxRow<pBest->szIdxRow) + ){ + pBest = pIdx; + } + } + } + if( pBest ){ + iRoot = pBest->tnum; + pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pBest); + } + + /* Open a read-only cursor, execute the OP_Count, close the cursor. */ + sqlite3VdbeAddOp4Int(v, OP_OpenRead, iCsr, (int)iRoot, iDb, 1); + if( pKeyInfo ){ + sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO); + } + assignAggregateRegisters(pParse, pAggInfo); + sqlite3VdbeAddOp2(v, OP_Count, iCsr, AggInfoFuncReg(pAggInfo,0)); + sqlite3VdbeAddOp1(v, OP_Close, iCsr); + explainSimpleCount(pParse, pTab, pBest); + }else{ + int regAcc = 0; /* "populate accumulators" flag */ + ExprList *pDistinct = 0; + u16 distFlag = 0; + int eDist; + + /* If there are accumulator registers but no min() or max() functions + ** without FILTER clauses, allocate register regAcc. Register regAcc + ** will contain 0 the first time the inner loop runs, and 1 thereafter. + ** The code generated by updateAccumulator() uses this to ensure + ** that the accumulator registers are (a) updated only once if + ** there are no min() or max functions or (b) always updated for the + ** first row visited by the aggregate, so that they are updated at + ** least once even if the FILTER clause means the min() or max() + ** function visits zero rows. */ + if( pAggInfo->nAccumulator ){ + for(i=0; i<pAggInfo->nFunc; i++){ + if( ExprHasProperty(pAggInfo->aFunc[i].pFExpr, EP_WinFunc) ){ + continue; + } + if( pAggInfo->aFunc[i].pFunc->funcFlags&SQLITE_FUNC_NEEDCOLL ){ + break; + } + } + if( i==pAggInfo->nFunc ){ + regAcc = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Integer, 0, regAcc); + } + }else if( pAggInfo->nFunc==1 && pAggInfo->aFunc[0].iDistinct>=0 ){ + assert( ExprUseXList(pAggInfo->aFunc[0].pFExpr) ); + pDistinct = pAggInfo->aFunc[0].pFExpr->x.pList; + distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0; + } + assignAggregateRegisters(pParse, pAggInfo); + + /* This case runs if the aggregate has no GROUP BY clause. The + ** processing is much simpler since there is only a single row + ** of output. + */ + assert( p->pGroupBy==0 ); + resetAccumulator(pParse, pAggInfo); + + /* If this query is a candidate for the min/max optimization, then + ** minMaxFlag will have been previously set to either + ** WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX and pMinMaxOrderBy will + ** be an appropriate ORDER BY expression for the optimization. + */ + assert( minMaxFlag==WHERE_ORDERBY_NORMAL || pMinMaxOrderBy!=0 ); + assert( pMinMaxOrderBy==0 || pMinMaxOrderBy->nExpr==1 ); + + TREETRACE(0x2,pParse,p,("WhereBegin\n")); + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMaxOrderBy, + pDistinct, p, minMaxFlag|distFlag, 0); + if( pWInfo==0 ){ + goto select_end; + } + TREETRACE(0x2,pParse,p,("WhereBegin returns\n")); + eDist = sqlite3WhereIsDistinct(pWInfo); + updateAccumulator(pParse, regAcc, pAggInfo, eDist); + if( eDist!=WHERE_DISTINCT_NOOP ){ + struct AggInfo_func *pF = pAggInfo->aFunc; + if( pF ){ + fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr); + } + } + + if( regAcc ) sqlite3VdbeAddOp2(v, OP_Integer, 1, regAcc); + if( minMaxFlag ){ + sqlite3WhereMinMaxOptEarlyOut(v, pWInfo); + } + TREETRACE(0x2,pParse,p,("WhereEnd\n")); + sqlite3WhereEnd(pWInfo); + finalizeAggFunctions(pParse, pAggInfo); + } + + sSort.pOrderBy = 0; + sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL); + selectInnerLoop(pParse, p, -1, 0, 0, + pDest, addrEnd, addrEnd); + } + sqlite3VdbeResolveLabel(v, addrEnd); + + } /* endif aggregate query */ + + if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){ + explainTempTable(pParse, "DISTINCT"); + } + + /* If there is an ORDER BY clause, then we need to sort the results + ** and send them to the callback one by one. + */ + if( sSort.pOrderBy ){ + assert( p->pEList==pEList ); + generateSortTail(pParse, p, &sSort, pEList->nExpr, pDest); + } + + /* Jump here to skip this query + */ + sqlite3VdbeResolveLabel(v, iEnd); + + /* The SELECT has been coded. If there is an error in the Parse structure, + ** set the return code to 1. Otherwise 0. */ + rc = (pParse->nErr>0); + + /* Control jumps to here if an error is encountered above, or upon + ** successful coding of the SELECT. + */ +select_end: + assert( db->mallocFailed==0 || db->mallocFailed==1 ); + assert( db->mallocFailed==0 || pParse->nErr!=0 ); + sqlite3ExprListDelete(db, pMinMaxOrderBy); +#ifdef SQLITE_DEBUG + if( pAggInfo && !db->mallocFailed ){ + for(i=0; i<pAggInfo->nColumn; i++){ + Expr *pExpr = pAggInfo->aCol[i].pCExpr; + if( pExpr==0 ) continue; + assert( pExpr->pAggInfo==pAggInfo ); + assert( pExpr->iAgg==i ); + } + for(i=0; i<pAggInfo->nFunc; i++){ + Expr *pExpr = pAggInfo->aFunc[i].pFExpr; + assert( pExpr!=0 ); + assert( pExpr->pAggInfo==pAggInfo ); + assert( pExpr->iAgg==i ); + } + } +#endif + +#if TREETRACE_ENABLED + TREETRACE(0x1,pParse,p,("end processing\n")); + if( (sqlite3TreeTrace & 0x40000)!=0 && ExplainQueryPlanParent(pParse)==0 ){ + sqlite3TreeViewSelect(0, p, 0); + } +#endif + ExplainQueryPlanPop(pParse); + return rc; +} |