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Diffstat (limited to 'src/window.c')
| -rw-r--r-- | src/window.c | 3103 |
1 files changed, 3103 insertions, 0 deletions
diff --git a/src/window.c b/src/window.c new file mode 100644 index 0000000..f13ea8b --- /dev/null +++ b/src/window.c @@ -0,0 +1,3103 @@ +/* +** 2018 May 08 +** +** 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. +** +************************************************************************* +*/ +#include "sqliteInt.h" + +#ifndef SQLITE_OMIT_WINDOWFUNC + +/* +** SELECT REWRITING +** +** Any SELECT statement that contains one or more window functions in +** either the select list or ORDER BY clause (the only two places window +** functions may be used) is transformed by function sqlite3WindowRewrite() +** in order to support window function processing. For example, with the +** schema: +** +** CREATE TABLE t1(a, b, c, d, e, f, g); +** +** the statement: +** +** SELECT a+1, max(b) OVER (PARTITION BY c ORDER BY d) FROM t1 ORDER BY e; +** +** is transformed to: +** +** SELECT a+1, max(b) OVER (PARTITION BY c ORDER BY d) FROM ( +** SELECT a, e, c, d, b FROM t1 ORDER BY c, d +** ) ORDER BY e; +** +** The flattening optimization is disabled when processing this transformed +** SELECT statement. This allows the implementation of the window function +** (in this case max()) to process rows sorted in order of (c, d), which +** makes things easier for obvious reasons. More generally: +** +** * FROM, WHERE, GROUP BY and HAVING clauses are all moved to +** the sub-query. +** +** * ORDER BY, LIMIT and OFFSET remain part of the parent query. +** +** * Terminals from each of the expression trees that make up the +** select-list and ORDER BY expressions in the parent query are +** selected by the sub-query. For the purposes of the transformation, +** terminals are column references and aggregate functions. +** +** If there is more than one window function in the SELECT that uses +** the same window declaration (the OVER bit), then a single scan may +** be used to process more than one window function. For example: +** +** SELECT max(b) OVER (PARTITION BY c ORDER BY d), +** min(e) OVER (PARTITION BY c ORDER BY d) +** FROM t1; +** +** is transformed in the same way as the example above. However: +** +** SELECT max(b) OVER (PARTITION BY c ORDER BY d), +** min(e) OVER (PARTITION BY a ORDER BY b) +** FROM t1; +** +** Must be transformed to: +** +** SELECT max(b) OVER (PARTITION BY c ORDER BY d) FROM ( +** SELECT e, min(e) OVER (PARTITION BY a ORDER BY b), c, d, b FROM +** SELECT a, e, c, d, b FROM t1 ORDER BY a, b +** ) ORDER BY c, d +** ) ORDER BY e; +** +** so that both min() and max() may process rows in the order defined by +** their respective window declarations. +** +** INTERFACE WITH SELECT.C +** +** When processing the rewritten SELECT statement, code in select.c calls +** sqlite3WhereBegin() to begin iterating through the results of the +** sub-query, which is always implemented as a co-routine. It then calls +** sqlite3WindowCodeStep() to process rows and finish the scan by calling +** sqlite3WhereEnd(). +** +** sqlite3WindowCodeStep() generates VM code so that, for each row returned +** by the sub-query a sub-routine (OP_Gosub) coded by select.c is invoked. +** When the sub-routine is invoked: +** +** * The results of all window-functions for the row are stored +** in the associated Window.regResult registers. +** +** * The required terminal values are stored in the current row of +** temp table Window.iEphCsr. +** +** In some cases, depending on the window frame and the specific window +** functions invoked, sqlite3WindowCodeStep() caches each entire partition +** in a temp table before returning any rows. In other cases it does not. +** This detail is encapsulated within this file, the code generated by +** select.c is the same in either case. +** +** BUILT-IN WINDOW FUNCTIONS +** +** This implementation features the following built-in window functions: +** +** row_number() +** rank() +** dense_rank() +** percent_rank() +** cume_dist() +** ntile(N) +** lead(expr [, offset [, default]]) +** lag(expr [, offset [, default]]) +** first_value(expr) +** last_value(expr) +** nth_value(expr, N) +** +** These are the same built-in window functions supported by Postgres. +** Although the behaviour of aggregate window functions (functions that +** can be used as either aggregates or window funtions) allows them to +** be implemented using an API, built-in window functions are much more +** esoteric. Additionally, some window functions (e.g. nth_value()) +** may only be implemented by caching the entire partition in memory. +** As such, some built-in window functions use the same API as aggregate +** window functions and some are implemented directly using VDBE +** instructions. Additionally, for those functions that use the API, the +** window frame is sometimes modified before the SELECT statement is +** rewritten. For example, regardless of the specified window frame, the +** row_number() function always uses: +** +** ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW +** +** See sqlite3WindowUpdate() for details. +** +** As well as some of the built-in window functions, aggregate window +** functions min() and max() are implemented using VDBE instructions if +** the start of the window frame is declared as anything other than +** UNBOUNDED PRECEDING. +*/ + +/* +** Implementation of built-in window function row_number(). Assumes that the +** window frame has been coerced to: +** +** ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW +*/ +static void row_numberStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + i64 *p = (i64*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ) (*p)++; + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); +} +static void row_numberValueFunc(sqlite3_context *pCtx){ + i64 *p = (i64*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + sqlite3_result_int64(pCtx, (p ? *p : 0)); +} + +/* +** Context object type used by rank(), dense_rank(), percent_rank() and +** cume_dist(). +*/ +struct CallCount { + i64 nValue; + i64 nStep; + i64 nTotal; +}; + +/* +** Implementation of built-in window function dense_rank(). Assumes that +** the window frame has been set to: +** +** RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW +*/ +static void dense_rankStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct CallCount *p; + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ) p->nStep = 1; + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); +} +static void dense_rankValueFunc(sqlite3_context *pCtx){ + struct CallCount *p; + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + if( p->nStep ){ + p->nValue++; + p->nStep = 0; + } + sqlite3_result_int64(pCtx, p->nValue); + } +} + +/* +** Implementation of built-in window function nth_value(). This +** implementation is used in "slow mode" only - when the EXCLUDE clause +** is not set to the default value "NO OTHERS". +*/ +struct NthValueCtx { + i64 nStep; + sqlite3_value *pValue; +}; +static void nth_valueStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct NthValueCtx *p; + p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + i64 iVal; + switch( sqlite3_value_numeric_type(apArg[1]) ){ + case SQLITE_INTEGER: + iVal = sqlite3_value_int64(apArg[1]); + break; + case SQLITE_FLOAT: { + double fVal = sqlite3_value_double(apArg[1]); + if( ((i64)fVal)!=fVal ) goto error_out; + iVal = (i64)fVal; + break; + } + default: + goto error_out; + } + if( iVal<=0 ) goto error_out; + + p->nStep++; + if( iVal==p->nStep ){ + p->pValue = sqlite3_value_dup(apArg[0]); + if( !p->pValue ){ + sqlite3_result_error_nomem(pCtx); + } + } + } + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); + return; + + error_out: + sqlite3_result_error( + pCtx, "second argument to nth_value must be a positive integer", -1 + ); +} +static void nth_valueFinalizeFunc(sqlite3_context *pCtx){ + struct NthValueCtx *p; + p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, 0); + if( p && p->pValue ){ + sqlite3_result_value(pCtx, p->pValue); + sqlite3_value_free(p->pValue); + p->pValue = 0; + } +} +#define nth_valueInvFunc noopStepFunc +#define nth_valueValueFunc noopValueFunc + +static void first_valueStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct NthValueCtx *p; + p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p && p->pValue==0 ){ + p->pValue = sqlite3_value_dup(apArg[0]); + if( !p->pValue ){ + sqlite3_result_error_nomem(pCtx); + } + } + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); +} +static void first_valueFinalizeFunc(sqlite3_context *pCtx){ + struct NthValueCtx *p; + p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p && p->pValue ){ + sqlite3_result_value(pCtx, p->pValue); + sqlite3_value_free(p->pValue); + p->pValue = 0; + } +} +#define first_valueInvFunc noopStepFunc +#define first_valueValueFunc noopValueFunc + +/* +** Implementation of built-in window function rank(). Assumes that +** the window frame has been set to: +** +** RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW +*/ +static void rankStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct CallCount *p; + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + p->nStep++; + if( p->nValue==0 ){ + p->nValue = p->nStep; + } + } + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); +} +static void rankValueFunc(sqlite3_context *pCtx){ + struct CallCount *p; + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + sqlite3_result_int64(pCtx, p->nValue); + p->nValue = 0; + } +} + +/* +** Implementation of built-in window function percent_rank(). Assumes that +** the window frame has been set to: +** +** GROUPS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING +*/ +static void percent_rankStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct CallCount *p; + UNUSED_PARAMETER(nArg); assert( nArg==0 ); + UNUSED_PARAMETER(apArg); + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + p->nTotal++; + } +} +static void percent_rankInvFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct CallCount *p; + UNUSED_PARAMETER(nArg); assert( nArg==0 ); + UNUSED_PARAMETER(apArg); + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + p->nStep++; +} +static void percent_rankValueFunc(sqlite3_context *pCtx){ + struct CallCount *p; + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + p->nValue = p->nStep; + if( p->nTotal>1 ){ + double r = (double)p->nValue / (double)(p->nTotal-1); + sqlite3_result_double(pCtx, r); + }else{ + sqlite3_result_double(pCtx, 0.0); + } + } +} +#define percent_rankFinalizeFunc percent_rankValueFunc + +/* +** Implementation of built-in window function cume_dist(). Assumes that +** the window frame has been set to: +** +** GROUPS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING +*/ +static void cume_distStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct CallCount *p; + UNUSED_PARAMETER(nArg); assert( nArg==0 ); + UNUSED_PARAMETER(apArg); + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + p->nTotal++; + } +} +static void cume_distInvFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct CallCount *p; + UNUSED_PARAMETER(nArg); assert( nArg==0 ); + UNUSED_PARAMETER(apArg); + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + p->nStep++; +} +static void cume_distValueFunc(sqlite3_context *pCtx){ + struct CallCount *p; + p = (struct CallCount*)sqlite3_aggregate_context(pCtx, 0); + if( p ){ + double r = (double)(p->nStep) / (double)(p->nTotal); + sqlite3_result_double(pCtx, r); + } +} +#define cume_distFinalizeFunc cume_distValueFunc + +/* +** Context object for ntile() window function. +*/ +struct NtileCtx { + i64 nTotal; /* Total rows in partition */ + i64 nParam; /* Parameter passed to ntile(N) */ + i64 iRow; /* Current row */ +}; + +/* +** Implementation of ntile(). This assumes that the window frame has +** been coerced to: +** +** ROWS CURRENT ROW AND UNBOUNDED FOLLOWING +*/ +static void ntileStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct NtileCtx *p; + assert( nArg==1 ); UNUSED_PARAMETER(nArg); + p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + if( p->nTotal==0 ){ + p->nParam = sqlite3_value_int64(apArg[0]); + if( p->nParam<=0 ){ + sqlite3_result_error( + pCtx, "argument of ntile must be a positive integer", -1 + ); + } + } + p->nTotal++; + } +} +static void ntileInvFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct NtileCtx *p; + assert( nArg==1 ); UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); + p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + p->iRow++; +} +static void ntileValueFunc(sqlite3_context *pCtx){ + struct NtileCtx *p; + p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p && p->nParam>0 ){ + int nSize = (p->nTotal / p->nParam); + if( nSize==0 ){ + sqlite3_result_int64(pCtx, p->iRow+1); + }else{ + i64 nLarge = p->nTotal - p->nParam*nSize; + i64 iSmall = nLarge*(nSize+1); + i64 iRow = p->iRow; + + assert( (nLarge*(nSize+1) + (p->nParam-nLarge)*nSize)==p->nTotal ); + + if( iRow<iSmall ){ + sqlite3_result_int64(pCtx, 1 + iRow/(nSize+1)); + }else{ + sqlite3_result_int64(pCtx, 1 + nLarge + (iRow-iSmall)/nSize); + } + } + } +} +#define ntileFinalizeFunc ntileValueFunc + +/* +** Context object for last_value() window function. +*/ +struct LastValueCtx { + sqlite3_value *pVal; + int nVal; +}; + +/* +** Implementation of last_value(). +*/ +static void last_valueStepFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct LastValueCtx *p; + UNUSED_PARAMETER(nArg); + p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p ){ + sqlite3_value_free(p->pVal); + p->pVal = sqlite3_value_dup(apArg[0]); + if( p->pVal==0 ){ + sqlite3_result_error_nomem(pCtx); + }else{ + p->nVal++; + } + } +} +static void last_valueInvFunc( + sqlite3_context *pCtx, + int nArg, + sqlite3_value **apArg +){ + struct LastValueCtx *p; + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(apArg); + p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( ALWAYS(p) ){ + p->nVal--; + if( p->nVal==0 ){ + sqlite3_value_free(p->pVal); + p->pVal = 0; + } + } +} +static void last_valueValueFunc(sqlite3_context *pCtx){ + struct LastValueCtx *p; + p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, 0); + if( p && p->pVal ){ + sqlite3_result_value(pCtx, p->pVal); + } +} +static void last_valueFinalizeFunc(sqlite3_context *pCtx){ + struct LastValueCtx *p; + p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p)); + if( p && p->pVal ){ + sqlite3_result_value(pCtx, p->pVal); + sqlite3_value_free(p->pVal); + p->pVal = 0; + } +} + +/* +** Static names for the built-in window function names. These static +** names are used, rather than string literals, so that FuncDef objects +** can be associated with a particular window function by direct +** comparison of the zName pointer. Example: +** +** if( pFuncDef->zName==row_valueName ){ ... } +*/ +static const char row_numberName[] = "row_number"; +static const char dense_rankName[] = "dense_rank"; +static const char rankName[] = "rank"; +static const char percent_rankName[] = "percent_rank"; +static const char cume_distName[] = "cume_dist"; +static const char ntileName[] = "ntile"; +static const char last_valueName[] = "last_value"; +static const char nth_valueName[] = "nth_value"; +static const char first_valueName[] = "first_value"; +static const char leadName[] = "lead"; +static const char lagName[] = "lag"; + +/* +** No-op implementations of xStep() and xFinalize(). Used as place-holders +** for built-in window functions that never call those interfaces. +** +** The noopValueFunc() is called but is expected to do nothing. The +** noopStepFunc() is never called, and so it is marked with NO_TEST to +** let the test coverage routine know not to expect this function to be +** invoked. +*/ +static void noopStepFunc( /*NO_TEST*/ + sqlite3_context *p, /*NO_TEST*/ + int n, /*NO_TEST*/ + sqlite3_value **a /*NO_TEST*/ +){ /*NO_TEST*/ + UNUSED_PARAMETER(p); /*NO_TEST*/ + UNUSED_PARAMETER(n); /*NO_TEST*/ + UNUSED_PARAMETER(a); /*NO_TEST*/ + assert(0); /*NO_TEST*/ +} /*NO_TEST*/ +static void noopValueFunc(sqlite3_context *p){ UNUSED_PARAMETER(p); /*no-op*/ } + +/* Window functions that use all window interfaces: xStep, xFinal, +** xValue, and xInverse */ +#define WINDOWFUNCALL(name,nArg,extra) { \ + nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0, \ + name ## StepFunc, name ## FinalizeFunc, name ## ValueFunc, \ + name ## InvFunc, name ## Name, {0} \ +} + +/* Window functions that are implemented using bytecode and thus have +** no-op routines for their methods */ +#define WINDOWFUNCNOOP(name,nArg,extra) { \ + nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0, \ + noopStepFunc, noopValueFunc, noopValueFunc, \ + noopStepFunc, name ## Name, {0} \ +} + +/* Window functions that use all window interfaces: xStep, the +** same routine for xFinalize and xValue and which never call +** xInverse. */ +#define WINDOWFUNCX(name,nArg,extra) { \ + nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0, \ + name ## StepFunc, name ## ValueFunc, name ## ValueFunc, \ + noopStepFunc, name ## Name, {0} \ +} + + +/* +** Register those built-in window functions that are not also aggregates. +*/ +void sqlite3WindowFunctions(void){ + static FuncDef aWindowFuncs[] = { + WINDOWFUNCX(row_number, 0, 0), + WINDOWFUNCX(dense_rank, 0, 0), + WINDOWFUNCX(rank, 0, 0), + WINDOWFUNCALL(percent_rank, 0, 0), + WINDOWFUNCALL(cume_dist, 0, 0), + WINDOWFUNCALL(ntile, 1, 0), + WINDOWFUNCALL(last_value, 1, 0), + WINDOWFUNCALL(nth_value, 2, 0), + WINDOWFUNCALL(first_value, 1, 0), + WINDOWFUNCNOOP(lead, 1, 0), + WINDOWFUNCNOOP(lead, 2, 0), + WINDOWFUNCNOOP(lead, 3, 0), + WINDOWFUNCNOOP(lag, 1, 0), + WINDOWFUNCNOOP(lag, 2, 0), + WINDOWFUNCNOOP(lag, 3, 0), + }; + sqlite3InsertBuiltinFuncs(aWindowFuncs, ArraySize(aWindowFuncs)); +} + +static Window *windowFind(Parse *pParse, Window *pList, const char *zName){ + Window *p; + for(p=pList; p; p=p->pNextWin){ + if( sqlite3StrICmp(p->zName, zName)==0 ) break; + } + if( p==0 ){ + sqlite3ErrorMsg(pParse, "no such window: %s", zName); + } + return p; +} + +/* +** This function is called immediately after resolving the function name +** for a window function within a SELECT statement. Argument pList is a +** linked list of WINDOW definitions for the current SELECT statement. +** Argument pFunc is the function definition just resolved and pWin +** is the Window object representing the associated OVER clause. This +** function updates the contents of pWin as follows: +** +** * If the OVER clause refered to a named window (as in "max(x) OVER win"), +** search list pList for a matching WINDOW definition, and update pWin +** accordingly. If no such WINDOW clause can be found, leave an error +** in pParse. +** +** * If the function is a built-in window function that requires the +** window to be coerced (see "BUILT-IN WINDOW FUNCTIONS" at the top +** of this file), pWin is updated here. +*/ +void sqlite3WindowUpdate( + Parse *pParse, + Window *pList, /* List of named windows for this SELECT */ + Window *pWin, /* Window frame to update */ + FuncDef *pFunc /* Window function definition */ +){ + if( pWin->zName && pWin->eFrmType==0 ){ + Window *p = windowFind(pParse, pList, pWin->zName); + if( p==0 ) return; + pWin->pPartition = sqlite3ExprListDup(pParse->db, p->pPartition, 0); + pWin->pOrderBy = sqlite3ExprListDup(pParse->db, p->pOrderBy, 0); + pWin->pStart = sqlite3ExprDup(pParse->db, p->pStart, 0); + pWin->pEnd = sqlite3ExprDup(pParse->db, p->pEnd, 0); + pWin->eStart = p->eStart; + pWin->eEnd = p->eEnd; + pWin->eFrmType = p->eFrmType; + pWin->eExclude = p->eExclude; + }else{ + sqlite3WindowChain(pParse, pWin, pList); + } + if( (pWin->eFrmType==TK_RANGE) + && (pWin->pStart || pWin->pEnd) + && (pWin->pOrderBy==0 || pWin->pOrderBy->nExpr!=1) + ){ + sqlite3ErrorMsg(pParse, + "RANGE with offset PRECEDING/FOLLOWING requires one ORDER BY expression" + ); + }else + if( pFunc->funcFlags & SQLITE_FUNC_WINDOW ){ + sqlite3 *db = pParse->db; + if( pWin->pFilter ){ + sqlite3ErrorMsg(pParse, + "FILTER clause may only be used with aggregate window functions" + ); + }else{ + struct WindowUpdate { + const char *zFunc; + int eFrmType; + int eStart; + int eEnd; + } aUp[] = { + { row_numberName, TK_ROWS, TK_UNBOUNDED, TK_CURRENT }, + { dense_rankName, TK_RANGE, TK_UNBOUNDED, TK_CURRENT }, + { rankName, TK_RANGE, TK_UNBOUNDED, TK_CURRENT }, + { percent_rankName, TK_GROUPS, TK_CURRENT, TK_UNBOUNDED }, + { cume_distName, TK_GROUPS, TK_FOLLOWING, TK_UNBOUNDED }, + { ntileName, TK_ROWS, TK_CURRENT, TK_UNBOUNDED }, + { leadName, TK_ROWS, TK_UNBOUNDED, TK_UNBOUNDED }, + { lagName, TK_ROWS, TK_UNBOUNDED, TK_CURRENT }, + }; + int i; + for(i=0; i<ArraySize(aUp); i++){ + if( pFunc->zName==aUp[i].zFunc ){ + sqlite3ExprDelete(db, pWin->pStart); + sqlite3ExprDelete(db, pWin->pEnd); + pWin->pEnd = pWin->pStart = 0; + pWin->eFrmType = aUp[i].eFrmType; + pWin->eStart = aUp[i].eStart; + pWin->eEnd = aUp[i].eEnd; + pWin->eExclude = 0; + if( pWin->eStart==TK_FOLLOWING ){ + pWin->pStart = sqlite3Expr(db, TK_INTEGER, "1"); + } + break; + } + } + } + } + pWin->pWFunc = pFunc; +} + +/* +** Context object passed through sqlite3WalkExprList() to +** selectWindowRewriteExprCb() by selectWindowRewriteEList(). +*/ +typedef struct WindowRewrite WindowRewrite; +struct WindowRewrite { + Window *pWin; + SrcList *pSrc; + ExprList *pSub; + Table *pTab; + Select *pSubSelect; /* Current sub-select, if any */ +}; + +/* +** Callback function used by selectWindowRewriteEList(). If necessary, +** this function appends to the output expression-list and updates +** expression (*ppExpr) in place. +*/ +static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){ + struct WindowRewrite *p = pWalker->u.pRewrite; + Parse *pParse = pWalker->pParse; + assert( p!=0 ); + assert( p->pWin!=0 ); + + /* If this function is being called from within a scalar sub-select + ** that used by the SELECT statement being processed, only process + ** TK_COLUMN expressions that refer to it (the outer SELECT). Do + ** not process aggregates or window functions at all, as they belong + ** to the scalar sub-select. */ + if( p->pSubSelect ){ + if( pExpr->op!=TK_COLUMN ){ + return WRC_Continue; + }else{ + int nSrc = p->pSrc->nSrc; + int i; + for(i=0; i<nSrc; i++){ + if( pExpr->iTable==p->pSrc->a[i].iCursor ) break; + } + if( i==nSrc ) return WRC_Continue; + } + } + + switch( pExpr->op ){ + + case TK_FUNCTION: + if( !ExprHasProperty(pExpr, EP_WinFunc) ){ + break; + }else{ + Window *pWin; + for(pWin=p->pWin; pWin; pWin=pWin->pNextWin){ + if( pExpr->y.pWin==pWin ){ + assert( pWin->pOwner==pExpr ); + return WRC_Prune; + } + } + } + /* no break */ deliberate_fall_through + + case TK_AGG_FUNCTION: + case TK_COLUMN: { + int iCol = -1; + if( pParse->db->mallocFailed ) return WRC_Abort; + if( p->pSub ){ + int i; + for(i=0; i<p->pSub->nExpr; i++){ + if( 0==sqlite3ExprCompare(0, p->pSub->a[i].pExpr, pExpr, -1) ){ + iCol = i; + break; + } + } + } + if( iCol<0 ){ + Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0); + if( pDup && pDup->op==TK_AGG_FUNCTION ) pDup->op = TK_FUNCTION; + p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup); + } + if( p->pSub ){ + int f = pExpr->flags & EP_Collate; + assert( ExprHasProperty(pExpr, EP_Static)==0 ); + ExprSetProperty(pExpr, EP_Static); + sqlite3ExprDelete(pParse->db, pExpr); + ExprClearProperty(pExpr, EP_Static); + memset(pExpr, 0, sizeof(Expr)); + + pExpr->op = TK_COLUMN; + pExpr->iColumn = (iCol<0 ? p->pSub->nExpr-1: iCol); + pExpr->iTable = p->pWin->iEphCsr; + pExpr->y.pTab = p->pTab; + pExpr->flags = f; + } + if( pParse->db->mallocFailed ) return WRC_Abort; + break; + } + + default: /* no-op */ + break; + } + + return WRC_Continue; +} +static int selectWindowRewriteSelectCb(Walker *pWalker, Select *pSelect){ + struct WindowRewrite *p = pWalker->u.pRewrite; + Select *pSave = p->pSubSelect; + if( pSave==pSelect ){ + return WRC_Continue; + }else{ + p->pSubSelect = pSelect; + sqlite3WalkSelect(pWalker, pSelect); + p->pSubSelect = pSave; + } + return WRC_Prune; +} + + +/* +** Iterate through each expression in expression-list pEList. For each: +** +** * TK_COLUMN, +** * aggregate function, or +** * window function with a Window object that is not a member of the +** Window list passed as the second argument (pWin). +** +** Append the node to output expression-list (*ppSub). And replace it +** with a TK_COLUMN that reads the (N-1)th element of table +** pWin->iEphCsr, where N is the number of elements in (*ppSub) after +** appending the new one. +*/ +static void selectWindowRewriteEList( + Parse *pParse, + Window *pWin, + SrcList *pSrc, + ExprList *pEList, /* Rewrite expressions in this list */ + Table *pTab, + ExprList **ppSub /* IN/OUT: Sub-select expression-list */ +){ + Walker sWalker; + WindowRewrite sRewrite; + + assert( pWin!=0 ); + memset(&sWalker, 0, sizeof(Walker)); + memset(&sRewrite, 0, sizeof(WindowRewrite)); + + sRewrite.pSub = *ppSub; + sRewrite.pWin = pWin; + sRewrite.pSrc = pSrc; + sRewrite.pTab = pTab; + + sWalker.pParse = pParse; + sWalker.xExprCallback = selectWindowRewriteExprCb; + sWalker.xSelectCallback = selectWindowRewriteSelectCb; + sWalker.u.pRewrite = &sRewrite; + + (void)sqlite3WalkExprList(&sWalker, pEList); + + *ppSub = sRewrite.pSub; +} + +/* +** Append a copy of each expression in expression-list pAppend to +** expression list pList. Return a pointer to the result list. +*/ +static ExprList *exprListAppendList( + Parse *pParse, /* Parsing context */ + ExprList *pList, /* List to which to append. Might be NULL */ + ExprList *pAppend, /* List of values to append. Might be NULL */ + int bIntToNull +){ + if( pAppend ){ + int i; + int nInit = pList ? pList->nExpr : 0; + for(i=0; i<pAppend->nExpr; i++){ + sqlite3 *db = pParse->db; + Expr *pDup = sqlite3ExprDup(db, pAppend->a[i].pExpr, 0); + if( db->mallocFailed ){ + sqlite3ExprDelete(db, pDup); + break; + } + if( bIntToNull ){ + int iDummy; + Expr *pSub; + pSub = sqlite3ExprSkipCollateAndLikely(pDup); + if( sqlite3ExprIsInteger(pSub, &iDummy) ){ + pSub->op = TK_NULL; + pSub->flags &= ~(EP_IntValue|EP_IsTrue|EP_IsFalse); + pSub->u.zToken = 0; + } + } + pList = sqlite3ExprListAppend(pParse, pList, pDup); + if( pList ) pList->a[nInit+i].fg.sortFlags = pAppend->a[i].fg.sortFlags; + } + } + return pList; +} + +/* +** When rewriting a query, if the new subquery in the FROM clause +** contains TK_AGG_FUNCTION nodes that refer to an outer query, +** then we have to increase the Expr->op2 values of those nodes +** due to the extra subquery layer that was added. +** +** See also the incrAggDepth() routine in resolve.c +*/ +static int sqlite3WindowExtraAggFuncDepth(Walker *pWalker, Expr *pExpr){ + if( pExpr->op==TK_AGG_FUNCTION + && pExpr->op2>=pWalker->walkerDepth + ){ + pExpr->op2++; + } + return WRC_Continue; +} + +static int disallowAggregatesInOrderByCb(Walker *pWalker, Expr *pExpr){ + if( pExpr->op==TK_AGG_FUNCTION && pExpr->pAggInfo==0 ){ + assert( !ExprHasProperty(pExpr, EP_IntValue) ); + sqlite3ErrorMsg(pWalker->pParse, + "misuse of aggregate: %s()", pExpr->u.zToken); + } + return WRC_Continue; +} + +/* +** If the SELECT statement passed as the second argument does not invoke +** any SQL window functions, this function is a no-op. Otherwise, it +** rewrites the SELECT statement so that window function xStep functions +** are invoked in the correct order as described under "SELECT REWRITING" +** at the top of this file. +*/ +int sqlite3WindowRewrite(Parse *pParse, Select *p){ + int rc = SQLITE_OK; + if( p->pWin + && p->pPrior==0 + && ALWAYS((p->selFlags & SF_WinRewrite)==0) + && ALWAYS(!IN_RENAME_OBJECT) + ){ + Vdbe *v = sqlite3GetVdbe(pParse); + sqlite3 *db = pParse->db; + Select *pSub = 0; /* The subquery */ + SrcList *pSrc = p->pSrc; + Expr *pWhere = p->pWhere; + ExprList *pGroupBy = p->pGroupBy; + Expr *pHaving = p->pHaving; + ExprList *pSort = 0; + + ExprList *pSublist = 0; /* Expression list for sub-query */ + Window *pMWin = p->pWin; /* Main window object */ + Window *pWin; /* Window object iterator */ + Table *pTab; + Walker w; + + u32 selFlags = p->selFlags; + + pTab = sqlite3DbMallocZero(db, sizeof(Table)); + if( pTab==0 ){ + return sqlite3ErrorToParser(db, SQLITE_NOMEM); + } + sqlite3AggInfoPersistWalkerInit(&w, pParse); + sqlite3WalkSelect(&w, p); + if( (p->selFlags & SF_Aggregate)==0 ){ + w.xExprCallback = disallowAggregatesInOrderByCb; + w.xSelectCallback = 0; + sqlite3WalkExprList(&w, p->pOrderBy); + } + + p->pSrc = 0; + p->pWhere = 0; + p->pGroupBy = 0; + p->pHaving = 0; + p->selFlags &= ~SF_Aggregate; + p->selFlags |= SF_WinRewrite; + + /* Create the ORDER BY clause for the sub-select. This is the concatenation + ** of the window PARTITION and ORDER BY clauses. Then, if this makes it + ** redundant, remove the ORDER BY from the parent SELECT. */ + pSort = exprListAppendList(pParse, 0, pMWin->pPartition, 1); + pSort = exprListAppendList(pParse, pSort, pMWin->pOrderBy, 1); + if( pSort && p->pOrderBy && p->pOrderBy->nExpr<=pSort->nExpr ){ + int nSave = pSort->nExpr; + pSort->nExpr = p->pOrderBy->nExpr; + if( sqlite3ExprListCompare(pSort, p->pOrderBy, -1)==0 ){ + sqlite3ExprListDelete(db, p->pOrderBy); + p->pOrderBy = 0; + } + pSort->nExpr = nSave; + } + + /* Assign a cursor number for the ephemeral table used to buffer rows. + ** The OpenEphemeral instruction is coded later, after it is known how + ** many columns the table will have. */ + pMWin->iEphCsr = pParse->nTab++; + pParse->nTab += 3; + + selectWindowRewriteEList(pParse, pMWin, pSrc, p->pEList, pTab, &pSublist); + selectWindowRewriteEList(pParse, pMWin, pSrc, p->pOrderBy, pTab, &pSublist); + pMWin->nBufferCol = (pSublist ? pSublist->nExpr : 0); + + /* Append the PARTITION BY and ORDER BY expressions to the to the + ** sub-select expression list. They are required to figure out where + ** boundaries for partitions and sets of peer rows lie. */ + pSublist = exprListAppendList(pParse, pSublist, pMWin->pPartition, 0); + pSublist = exprListAppendList(pParse, pSublist, pMWin->pOrderBy, 0); + + /* Append the arguments passed to each window function to the + ** sub-select expression list. Also allocate two registers for each + ** window function - one for the accumulator, another for interim + ** results. */ + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + ExprList *pArgs; + assert( ExprUseXList(pWin->pOwner) ); + assert( pWin->pWFunc!=0 ); + pArgs = pWin->pOwner->x.pList; + if( pWin->pWFunc->funcFlags & SQLITE_FUNC_SUBTYPE ){ + selectWindowRewriteEList(pParse, pMWin, pSrc, pArgs, pTab, &pSublist); + pWin->iArgCol = (pSublist ? pSublist->nExpr : 0); + pWin->bExprArgs = 1; + }else{ + pWin->iArgCol = (pSublist ? pSublist->nExpr : 0); + pSublist = exprListAppendList(pParse, pSublist, pArgs, 0); + } + if( pWin->pFilter ){ + Expr *pFilter = sqlite3ExprDup(db, pWin->pFilter, 0); + pSublist = sqlite3ExprListAppend(pParse, pSublist, pFilter); + } + pWin->regAccum = ++pParse->nMem; + pWin->regResult = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum); + } + + /* If there is no ORDER BY or PARTITION BY clause, and the window + ** function accepts zero arguments, and there are no other columns + ** selected (e.g. "SELECT row_number() OVER () FROM t1"), it is possible + ** that pSublist is still NULL here. Add a constant expression here to + ** keep everything legal in this case. + */ + if( pSublist==0 ){ + pSublist = sqlite3ExprListAppend(pParse, 0, + sqlite3Expr(db, TK_INTEGER, "0") + ); + } + + pSub = sqlite3SelectNew( + pParse, pSublist, pSrc, pWhere, pGroupBy, pHaving, pSort, 0, 0 + ); + SELECTTRACE(1,pParse,pSub, + ("New window-function subquery in FROM clause of (%u/%p)\n", + p->selId, p)); + p->pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0); + assert( pSub!=0 || p->pSrc==0 ); /* Due to db->mallocFailed test inside + ** of sqlite3DbMallocRawNN() called from + ** sqlite3SrcListAppend() */ + if( p->pSrc ){ + Table *pTab2; + p->pSrc->a[0].pSelect = pSub; + sqlite3SrcListAssignCursors(pParse, p->pSrc); + pSub->selFlags |= SF_Expanded|SF_OrderByReqd; + pTab2 = sqlite3ResultSetOfSelect(pParse, pSub, SQLITE_AFF_NONE); + pSub->selFlags |= (selFlags & SF_Aggregate); + if( pTab2==0 ){ + /* Might actually be some other kind of error, but in that case + ** pParse->nErr will be set, so if SQLITE_NOMEM is set, we will get + ** the correct error message regardless. */ + rc = SQLITE_NOMEM; + }else{ + memcpy(pTab, pTab2, sizeof(Table)); + pTab->tabFlags |= TF_Ephemeral; + p->pSrc->a[0].pTab = pTab; + pTab = pTab2; + memset(&w, 0, sizeof(w)); + w.xExprCallback = sqlite3WindowExtraAggFuncDepth; + w.xSelectCallback = sqlite3WalkerDepthIncrease; + w.xSelectCallback2 = sqlite3WalkerDepthDecrease; + sqlite3WalkSelect(&w, pSub); + } + }else{ + sqlite3SelectDelete(db, pSub); + } + if( db->mallocFailed ) rc = SQLITE_NOMEM; + + /* Defer deleting the temporary table pTab because if an error occurred, + ** there could still be references to that table embedded in the + ** result-set or ORDER BY clause of the SELECT statement p. */ + sqlite3ParserAddCleanup(pParse, sqlite3DbFree, pTab); + } + + assert( rc==SQLITE_OK || pParse->nErr!=0 ); + return rc; +} + +/* +** Unlink the Window object from the Select to which it is attached, +** if it is attached. +*/ +void sqlite3WindowUnlinkFromSelect(Window *p){ + if( p->ppThis ){ + *p->ppThis = p->pNextWin; + if( p->pNextWin ) p->pNextWin->ppThis = p->ppThis; + p->ppThis = 0; + } +} + +/* +** Free the Window object passed as the second argument. +*/ +void sqlite3WindowDelete(sqlite3 *db, Window *p){ + if( p ){ + sqlite3WindowUnlinkFromSelect(p); + sqlite3ExprDelete(db, p->pFilter); + sqlite3ExprListDelete(db, p->pPartition); + sqlite3ExprListDelete(db, p->pOrderBy); + sqlite3ExprDelete(db, p->pEnd); + sqlite3ExprDelete(db, p->pStart); + sqlite3DbFree(db, p->zName); + sqlite3DbFree(db, p->zBase); + sqlite3DbFree(db, p); + } +} + +/* +** Free the linked list of Window objects starting at the second argument. +*/ +void sqlite3WindowListDelete(sqlite3 *db, Window *p){ + while( p ){ + Window *pNext = p->pNextWin; + sqlite3WindowDelete(db, p); + p = pNext; + } +} + +/* +** The argument expression is an PRECEDING or FOLLOWING offset. The +** value should be a non-negative integer. If the value is not a +** constant, change it to NULL. The fact that it is then a non-negative +** integer will be caught later. But it is important not to leave +** variable values in the expression tree. +*/ +static Expr *sqlite3WindowOffsetExpr(Parse *pParse, Expr *pExpr){ + if( 0==sqlite3ExprIsConstant(pExpr) ){ + if( IN_RENAME_OBJECT ) sqlite3RenameExprUnmap(pParse, pExpr); + sqlite3ExprDelete(pParse->db, pExpr); + pExpr = sqlite3ExprAlloc(pParse->db, TK_NULL, 0, 0); + } + return pExpr; +} + +/* +** Allocate and return a new Window object describing a Window Definition. +*/ +Window *sqlite3WindowAlloc( + Parse *pParse, /* Parsing context */ + int eType, /* Frame type. TK_RANGE, TK_ROWS, TK_GROUPS, or 0 */ + int eStart, /* Start type: CURRENT, PRECEDING, FOLLOWING, UNBOUNDED */ + Expr *pStart, /* Start window size if TK_PRECEDING or FOLLOWING */ + int eEnd, /* End type: CURRENT, FOLLOWING, TK_UNBOUNDED, PRECEDING */ + Expr *pEnd, /* End window size if TK_FOLLOWING or PRECEDING */ + u8 eExclude /* EXCLUDE clause */ +){ + Window *pWin = 0; + int bImplicitFrame = 0; + + /* Parser assures the following: */ + assert( eType==0 || eType==TK_RANGE || eType==TK_ROWS || eType==TK_GROUPS ); + assert( eStart==TK_CURRENT || eStart==TK_PRECEDING + || eStart==TK_UNBOUNDED || eStart==TK_FOLLOWING ); + assert( eEnd==TK_CURRENT || eEnd==TK_FOLLOWING + || eEnd==TK_UNBOUNDED || eEnd==TK_PRECEDING ); + assert( (eStart==TK_PRECEDING || eStart==TK_FOLLOWING)==(pStart!=0) ); + assert( (eEnd==TK_FOLLOWING || eEnd==TK_PRECEDING)==(pEnd!=0) ); + + if( eType==0 ){ + bImplicitFrame = 1; + eType = TK_RANGE; + } + + /* Additionally, the + ** starting boundary type may not occur earlier in the following list than + ** the ending boundary type: + ** + ** UNBOUNDED PRECEDING + ** <expr> PRECEDING + ** CURRENT ROW + ** <expr> FOLLOWING + ** UNBOUNDED FOLLOWING + ** + ** The parser ensures that "UNBOUNDED PRECEDING" cannot be used as an ending + ** boundary, and than "UNBOUNDED FOLLOWING" cannot be used as a starting + ** frame boundary. + */ + if( (eStart==TK_CURRENT && eEnd==TK_PRECEDING) + || (eStart==TK_FOLLOWING && (eEnd==TK_PRECEDING || eEnd==TK_CURRENT)) + ){ + sqlite3ErrorMsg(pParse, "unsupported frame specification"); + goto windowAllocErr; + } + + pWin = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window)); + if( pWin==0 ) goto windowAllocErr; + pWin->eFrmType = eType; + pWin->eStart = eStart; + pWin->eEnd = eEnd; + if( eExclude==0 && OptimizationDisabled(pParse->db, SQLITE_WindowFunc) ){ + eExclude = TK_NO; + } + pWin->eExclude = eExclude; + pWin->bImplicitFrame = bImplicitFrame; + pWin->pEnd = sqlite3WindowOffsetExpr(pParse, pEnd); + pWin->pStart = sqlite3WindowOffsetExpr(pParse, pStart); + return pWin; + +windowAllocErr: + sqlite3ExprDelete(pParse->db, pEnd); + sqlite3ExprDelete(pParse->db, pStart); + return 0; +} + +/* +** Attach PARTITION and ORDER BY clauses pPartition and pOrderBy to window +** pWin. Also, if parameter pBase is not NULL, set pWin->zBase to the +** equivalent nul-terminated string. +*/ +Window *sqlite3WindowAssemble( + Parse *pParse, + Window *pWin, + ExprList *pPartition, + ExprList *pOrderBy, + Token *pBase +){ + if( pWin ){ + pWin->pPartition = pPartition; + pWin->pOrderBy = pOrderBy; + if( pBase ){ + pWin->zBase = sqlite3DbStrNDup(pParse->db, pBase->z, pBase->n); + } + }else{ + sqlite3ExprListDelete(pParse->db, pPartition); + sqlite3ExprListDelete(pParse->db, pOrderBy); + } + return pWin; +} + +/* +** Window *pWin has just been created from a WINDOW clause. Tokne pBase +** is the base window. Earlier windows from the same WINDOW clause are +** stored in the linked list starting at pWin->pNextWin. This function +** either updates *pWin according to the base specification, or else +** leaves an error in pParse. +*/ +void sqlite3WindowChain(Parse *pParse, Window *pWin, Window *pList){ + if( pWin->zBase ){ + sqlite3 *db = pParse->db; + Window *pExist = windowFind(pParse, pList, pWin->zBase); + if( pExist ){ + const char *zErr = 0; + /* Check for errors */ + if( pWin->pPartition ){ + zErr = "PARTITION clause"; + }else if( pExist->pOrderBy && pWin->pOrderBy ){ + zErr = "ORDER BY clause"; + }else if( pExist->bImplicitFrame==0 ){ + zErr = "frame specification"; + } + if( zErr ){ + sqlite3ErrorMsg(pParse, + "cannot override %s of window: %s", zErr, pWin->zBase + ); + }else{ + pWin->pPartition = sqlite3ExprListDup(db, pExist->pPartition, 0); + if( pExist->pOrderBy ){ + assert( pWin->pOrderBy==0 ); + pWin->pOrderBy = sqlite3ExprListDup(db, pExist->pOrderBy, 0); + } + sqlite3DbFree(db, pWin->zBase); + pWin->zBase = 0; + } + } + } +} + +/* +** Attach window object pWin to expression p. +*/ +void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){ + if( p ){ + assert( p->op==TK_FUNCTION ); + assert( pWin ); + p->y.pWin = pWin; + ExprSetProperty(p, EP_WinFunc); + pWin->pOwner = p; + if( (p->flags & EP_Distinct) && pWin->eFrmType!=TK_FILTER ){ + sqlite3ErrorMsg(pParse, + "DISTINCT is not supported for window functions" + ); + } + }else{ + sqlite3WindowDelete(pParse->db, pWin); + } +} + +/* +** Possibly link window pWin into the list at pSel->pWin (window functions +** to be processed as part of SELECT statement pSel). The window is linked +** in if either (a) there are no other windows already linked to this +** SELECT, or (b) the windows already linked use a compatible window frame. +*/ +void sqlite3WindowLink(Select *pSel, Window *pWin){ + if( pSel ){ + if( 0==pSel->pWin || 0==sqlite3WindowCompare(0, pSel->pWin, pWin, 0) ){ + pWin->pNextWin = pSel->pWin; + if( pSel->pWin ){ + pSel->pWin->ppThis = &pWin->pNextWin; + } + pSel->pWin = pWin; + pWin->ppThis = &pSel->pWin; + }else{ + if( sqlite3ExprListCompare(pWin->pPartition, pSel->pWin->pPartition,-1) ){ + pSel->selFlags |= SF_MultiPart; + } + } + } +} + +/* +** Return 0 if the two window objects are identical, 1 if they are +** different, or 2 if it cannot be determined if the objects are identical +** or not. Identical window objects can be processed in a single scan. +*/ +int sqlite3WindowCompare( + const Parse *pParse, + const Window *p1, + const Window *p2, + int bFilter +){ + int res; + if( NEVER(p1==0) || NEVER(p2==0) ) return 1; + if( p1->eFrmType!=p2->eFrmType ) return 1; + if( p1->eStart!=p2->eStart ) return 1; + if( p1->eEnd!=p2->eEnd ) return 1; + if( p1->eExclude!=p2->eExclude ) return 1; + if( sqlite3ExprCompare(pParse, p1->pStart, p2->pStart, -1) ) return 1; + if( sqlite3ExprCompare(pParse, p1->pEnd, p2->pEnd, -1) ) return 1; + if( (res = sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1)) ){ + return res; + } + if( (res = sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1)) ){ + return res; + } + if( bFilter ){ + if( (res = sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1)) ){ + return res; + } + } + return 0; +} + + +/* +** This is called by code in select.c before it calls sqlite3WhereBegin() +** to begin iterating through the sub-query results. It is used to allocate +** and initialize registers and cursors used by sqlite3WindowCodeStep(). +*/ +void sqlite3WindowCodeInit(Parse *pParse, Select *pSelect){ + int nEphExpr = pSelect->pSrc->a[0].pSelect->pEList->nExpr; + Window *pMWin = pSelect->pWin; + Window *pWin; + Vdbe *v = sqlite3GetVdbe(pParse); + + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pMWin->iEphCsr, nEphExpr); + sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+1, pMWin->iEphCsr); + sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+2, pMWin->iEphCsr); + sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+3, pMWin->iEphCsr); + + /* Allocate registers to use for PARTITION BY values, if any. Initialize + ** said registers to NULL. */ + if( pMWin->pPartition ){ + int nExpr = pMWin->pPartition->nExpr; + pMWin->regPart = pParse->nMem+1; + pParse->nMem += nExpr; + sqlite3VdbeAddOp3(v, OP_Null, 0, pMWin->regPart, pMWin->regPart+nExpr-1); + } + + pMWin->regOne = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regOne); + + if( pMWin->eExclude ){ + pMWin->regStartRowid = ++pParse->nMem; + pMWin->regEndRowid = ++pParse->nMem; + pMWin->csrApp = pParse->nTab++; + sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid); + sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid); + sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->csrApp, pMWin->iEphCsr); + return; + } + + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + FuncDef *p = pWin->pWFunc; + if( (p->funcFlags & SQLITE_FUNC_MINMAX) && pWin->eStart!=TK_UNBOUNDED ){ + /* The inline versions of min() and max() require a single ephemeral + ** table and 3 registers. The registers are used as follows: + ** + ** regApp+0: slot to copy min()/max() argument to for MakeRecord + ** regApp+1: integer value used to ensure keys are unique + ** regApp+2: output of MakeRecord + */ + ExprList *pList; + KeyInfo *pKeyInfo; + assert( ExprUseXList(pWin->pOwner) ); + pList = pWin->pOwner->x.pList; + pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pList, 0, 0); + pWin->csrApp = pParse->nTab++; + pWin->regApp = pParse->nMem+1; + pParse->nMem += 3; + if( pKeyInfo && pWin->pWFunc->zName[1]=='i' ){ + assert( pKeyInfo->aSortFlags[0]==0 ); + pKeyInfo->aSortFlags[0] = KEYINFO_ORDER_DESC; + } + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pWin->csrApp, 2); + sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO); + sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1); + } + else if( p->zName==nth_valueName || p->zName==first_valueName ){ + /* Allocate two registers at pWin->regApp. These will be used to + ** store the start and end index of the current frame. */ + pWin->regApp = pParse->nMem+1; + pWin->csrApp = pParse->nTab++; + pParse->nMem += 2; + sqlite3VdbeAddOp2(v, OP_OpenDup, pWin->csrApp, pMWin->iEphCsr); + } + else if( p->zName==leadName || p->zName==lagName ){ + pWin->csrApp = pParse->nTab++; + sqlite3VdbeAddOp2(v, OP_OpenDup, pWin->csrApp, pMWin->iEphCsr); + } + } +} + +#define WINDOW_STARTING_INT 0 +#define WINDOW_ENDING_INT 1 +#define WINDOW_NTH_VALUE_INT 2 +#define WINDOW_STARTING_NUM 3 +#define WINDOW_ENDING_NUM 4 + +/* +** A "PRECEDING <expr>" (eCond==0) or "FOLLOWING <expr>" (eCond==1) or the +** value of the second argument to nth_value() (eCond==2) has just been +** evaluated and the result left in register reg. This function generates VM +** code to check that the value is a non-negative integer and throws an +** exception if it is not. +*/ +static void windowCheckValue(Parse *pParse, int reg, int eCond){ + static const char *azErr[] = { + "frame starting offset must be a non-negative integer", + "frame ending offset must be a non-negative integer", + "second argument to nth_value must be a positive integer", + "frame starting offset must be a non-negative number", + "frame ending offset must be a non-negative number", + }; + static int aOp[] = { OP_Ge, OP_Ge, OP_Gt, OP_Ge, OP_Ge }; + Vdbe *v = sqlite3GetVdbe(pParse); + int regZero = sqlite3GetTempReg(pParse); + assert( eCond>=0 && eCond<ArraySize(azErr) ); + sqlite3VdbeAddOp2(v, OP_Integer, 0, regZero); + if( eCond>=WINDOW_STARTING_NUM ){ + int regString = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC); + sqlite3VdbeAddOp3(v, OP_Ge, regString, sqlite3VdbeCurrentAddr(v)+2, reg); + sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC|SQLITE_JUMPIFNULL); + VdbeCoverage(v); + assert( eCond==3 || eCond==4 ); + VdbeCoverageIf(v, eCond==3); + VdbeCoverageIf(v, eCond==4); + }else{ + sqlite3VdbeAddOp2(v, OP_MustBeInt, reg, sqlite3VdbeCurrentAddr(v)+2); + VdbeCoverage(v); + assert( eCond==0 || eCond==1 || eCond==2 ); + VdbeCoverageIf(v, eCond==0); + VdbeCoverageIf(v, eCond==1); + VdbeCoverageIf(v, eCond==2); + } + sqlite3VdbeAddOp3(v, aOp[eCond], regZero, sqlite3VdbeCurrentAddr(v)+2, reg); + sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC); + VdbeCoverageNeverNullIf(v, eCond==0); /* NULL case captured by */ + VdbeCoverageNeverNullIf(v, eCond==1); /* the OP_MustBeInt */ + VdbeCoverageNeverNullIf(v, eCond==2); + VdbeCoverageNeverNullIf(v, eCond==3); /* NULL case caught by */ + VdbeCoverageNeverNullIf(v, eCond==4); /* the OP_Ge */ + sqlite3MayAbort(pParse); + sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_ERROR, OE_Abort); + sqlite3VdbeAppendP4(v, (void*)azErr[eCond], P4_STATIC); + sqlite3ReleaseTempReg(pParse, regZero); +} + +/* +** Return the number of arguments passed to the window-function associated +** with the object passed as the only argument to this function. +*/ +static int windowArgCount(Window *pWin){ + const ExprList *pList; + assert( ExprUseXList(pWin->pOwner) ); + pList = pWin->pOwner->x.pList; + return (pList ? pList->nExpr : 0); +} + +typedef struct WindowCodeArg WindowCodeArg; +typedef struct WindowCsrAndReg WindowCsrAndReg; + +/* +** See comments above struct WindowCodeArg. +*/ +struct WindowCsrAndReg { + int csr; /* Cursor number */ + int reg; /* First in array of peer values */ +}; + +/* +** A single instance of this structure is allocated on the stack by +** sqlite3WindowCodeStep() and a pointer to it passed to the various helper +** routines. This is to reduce the number of arguments required by each +** helper function. +** +** regArg: +** Each window function requires an accumulator register (just as an +** ordinary aggregate function does). This variable is set to the first +** in an array of accumulator registers - one for each window function +** in the WindowCodeArg.pMWin list. +** +** eDelete: +** The window functions implementation sometimes caches the input rows +** that it processes in a temporary table. If it is not zero, this +** variable indicates when rows may be removed from the temp table (in +** order to reduce memory requirements - it would always be safe just +** to leave them there). Possible values for eDelete are: +** +** WINDOW_RETURN_ROW: +** An input row can be discarded after it is returned to the caller. +** +** WINDOW_AGGINVERSE: +** An input row can be discarded after the window functions xInverse() +** callbacks have been invoked in it. +** +** WINDOW_AGGSTEP: +** An input row can be discarded after the window functions xStep() +** callbacks have been invoked in it. +** +** start,current,end +** Consider a window-frame similar to the following: +** +** (ORDER BY a, b GROUPS BETWEEN 2 PRECEDING AND 2 FOLLOWING) +** +** The windows functions implmentation caches the input rows in a temp +** table, sorted by "a, b" (it actually populates the cache lazily, and +** aggressively removes rows once they are no longer required, but that's +** a mere detail). It keeps three cursors open on the temp table. One +** (current) that points to the next row to return to the query engine +** once its window function values have been calculated. Another (end) +** points to the next row to call the xStep() method of each window function +** on (so that it is 2 groups ahead of current). And a third (start) that +** points to the next row to call the xInverse() method of each window +** function on. +** +** Each cursor (start, current and end) consists of a VDBE cursor +** (WindowCsrAndReg.csr) and an array of registers (starting at +** WindowCodeArg.reg) that always contains a copy of the peer values +** read from the corresponding cursor. +** +** Depending on the window-frame in question, all three cursors may not +** be required. In this case both WindowCodeArg.csr and reg are set to +** 0. +*/ +struct WindowCodeArg { + Parse *pParse; /* Parse context */ + Window *pMWin; /* First in list of functions being processed */ + Vdbe *pVdbe; /* VDBE object */ + int addrGosub; /* OP_Gosub to this address to return one row */ + int regGosub; /* Register used with OP_Gosub(addrGosub) */ + int regArg; /* First in array of accumulator registers */ + int eDelete; /* See above */ + int regRowid; + + WindowCsrAndReg start; + WindowCsrAndReg current; + WindowCsrAndReg end; +}; + +/* +** Generate VM code to read the window frames peer values from cursor csr into +** an array of registers starting at reg. +*/ +static void windowReadPeerValues( + WindowCodeArg *p, + int csr, + int reg +){ + Window *pMWin = p->pMWin; + ExprList *pOrderBy = pMWin->pOrderBy; + if( pOrderBy ){ + Vdbe *v = sqlite3GetVdbe(p->pParse); + ExprList *pPart = pMWin->pPartition; + int iColOff = pMWin->nBufferCol + (pPart ? pPart->nExpr : 0); + int i; + for(i=0; i<pOrderBy->nExpr; i++){ + sqlite3VdbeAddOp3(v, OP_Column, csr, iColOff+i, reg+i); + } + } +} + +/* +** Generate VM code to invoke either xStep() (if bInverse is 0) or +** xInverse (if bInverse is non-zero) for each window function in the +** linked list starting at pMWin. Or, for built-in window functions +** that do not use the standard function API, generate the required +** inline VM code. +** +** If argument csr is greater than or equal to 0, then argument reg is +** the first register in an array of registers guaranteed to be large +** enough to hold the array of arguments for each function. In this case +** the arguments are extracted from the current row of csr into the +** array of registers before invoking OP_AggStep or OP_AggInverse +** +** Or, if csr is less than zero, then the array of registers at reg is +** already populated with all columns from the current row of the sub-query. +** +** If argument regPartSize is non-zero, then it is a register containing the +** number of rows in the current partition. +*/ +static void windowAggStep( + WindowCodeArg *p, + Window *pMWin, /* Linked list of window functions */ + int csr, /* Read arguments from this cursor */ + int bInverse, /* True to invoke xInverse instead of xStep */ + int reg /* Array of registers */ +){ + Parse *pParse = p->pParse; + Vdbe *v = sqlite3GetVdbe(pParse); + Window *pWin; + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + FuncDef *pFunc = pWin->pWFunc; + int regArg; + int nArg = pWin->bExprArgs ? 0 : windowArgCount(pWin); + int i; + + assert( bInverse==0 || pWin->eStart!=TK_UNBOUNDED ); + + /* All OVER clauses in the same window function aggregate step must + ** be the same. */ + assert( pWin==pMWin || sqlite3WindowCompare(pParse,pWin,pMWin,0)!=1 ); + + for(i=0; i<nArg; i++){ + if( i!=1 || pFunc->zName!=nth_valueName ){ + sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i); + }else{ + sqlite3VdbeAddOp3(v, OP_Column, pMWin->iEphCsr, pWin->iArgCol+i, reg+i); + } + } + regArg = reg; + + if( pMWin->regStartRowid==0 + && (pFunc->funcFlags & SQLITE_FUNC_MINMAX) + && (pWin->eStart!=TK_UNBOUNDED) + ){ + int addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regArg); + VdbeCoverage(v); + if( bInverse==0 ){ + sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1, 1); + sqlite3VdbeAddOp2(v, OP_SCopy, regArg, pWin->regApp); + sqlite3VdbeAddOp3(v, OP_MakeRecord, pWin->regApp, 2, pWin->regApp+2); + sqlite3VdbeAddOp2(v, OP_IdxInsert, pWin->csrApp, pWin->regApp+2); + }else{ + sqlite3VdbeAddOp4Int(v, OP_SeekGE, pWin->csrApp, 0, regArg, 1); + VdbeCoverageNeverTaken(v); + sqlite3VdbeAddOp1(v, OP_Delete, pWin->csrApp); + sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2); + } + sqlite3VdbeJumpHere(v, addrIsNull); + }else if( pWin->regApp ){ + assert( pFunc->zName==nth_valueName + || pFunc->zName==first_valueName + ); + assert( bInverse==0 || bInverse==1 ); + sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1-bInverse, 1); + }else if( pFunc->xSFunc!=noopStepFunc ){ + int addrIf = 0; + if( pWin->pFilter ){ + int regTmp; + assert( ExprUseXList(pWin->pOwner) ); + assert( pWin->bExprArgs || !nArg ||nArg==pWin->pOwner->x.pList->nExpr ); + assert( pWin->bExprArgs || nArg ||pWin->pOwner->x.pList==0 ); + regTmp = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+nArg,regTmp); + addrIf = sqlite3VdbeAddOp3(v, OP_IfNot, regTmp, 0, 1); + VdbeCoverage(v); + sqlite3ReleaseTempReg(pParse, regTmp); + } + + if( pWin->bExprArgs ){ + int iOp = sqlite3VdbeCurrentAddr(v); + int iEnd; + + assert( ExprUseXList(pWin->pOwner) ); + nArg = pWin->pOwner->x.pList->nExpr; + regArg = sqlite3GetTempRange(pParse, nArg); + sqlite3ExprCodeExprList(pParse, pWin->pOwner->x.pList, regArg, 0, 0); + + for(iEnd=sqlite3VdbeCurrentAddr(v); iOp<iEnd; iOp++){ + VdbeOp *pOp = sqlite3VdbeGetOp(v, iOp); + if( pOp->opcode==OP_Column && pOp->p1==pMWin->iEphCsr ){ + pOp->p1 = csr; + } + } + } + if( pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){ + CollSeq *pColl; + assert( nArg>0 ); + assert( ExprUseXList(pWin->pOwner) ); + pColl = sqlite3ExprNNCollSeq(pParse, pWin->pOwner->x.pList->a[0].pExpr); + sqlite3VdbeAddOp4(v, OP_CollSeq, 0,0,0, (const char*)pColl, P4_COLLSEQ); + } + sqlite3VdbeAddOp3(v, bInverse? OP_AggInverse : OP_AggStep, + bInverse, regArg, pWin->regAccum); + sqlite3VdbeAppendP4(v, pFunc, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, (u8)nArg); + if( pWin->bExprArgs ){ + sqlite3ReleaseTempRange(pParse, regArg, nArg); + } + if( addrIf ) sqlite3VdbeJumpHere(v, addrIf); + } + } +} + +/* +** Values that may be passed as the second argument to windowCodeOp(). +*/ +#define WINDOW_RETURN_ROW 1 +#define WINDOW_AGGINVERSE 2 +#define WINDOW_AGGSTEP 3 + +/* +** Generate VM code to invoke either xValue() (bFin==0) or xFinalize() +** (bFin==1) for each window function in the linked list starting at +** pMWin. Or, for built-in window-functions that do not use the standard +** API, generate the equivalent VM code. +*/ +static void windowAggFinal(WindowCodeArg *p, int bFin){ + Parse *pParse = p->pParse; + Window *pMWin = p->pMWin; + Vdbe *v = sqlite3GetVdbe(pParse); + Window *pWin; + + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + if( pMWin->regStartRowid==0 + && (pWin->pWFunc->funcFlags & SQLITE_FUNC_MINMAX) + && (pWin->eStart!=TK_UNBOUNDED) + ){ + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult); + sqlite3VdbeAddOp1(v, OP_Last, pWin->csrApp); + VdbeCoverage(v); + sqlite3VdbeAddOp3(v, OP_Column, pWin->csrApp, 0, pWin->regResult); + sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2); + }else if( pWin->regApp ){ + assert( pMWin->regStartRowid==0 ); + }else{ + int nArg = windowArgCount(pWin); + if( bFin ){ + sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, nArg); + sqlite3VdbeAppendP4(v, pWin->pWFunc, P4_FUNCDEF); + sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult); + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum); + }else{ + sqlite3VdbeAddOp3(v, OP_AggValue,pWin->regAccum,nArg,pWin->regResult); + sqlite3VdbeAppendP4(v, pWin->pWFunc, P4_FUNCDEF); + } + } + } +} + +/* +** Generate code to calculate the current values of all window functions in the +** p->pMWin list by doing a full scan of the current window frame. Store the +** results in the Window.regResult registers, ready to return the upper +** layer. +*/ +static void windowFullScan(WindowCodeArg *p){ + Window *pWin; + Parse *pParse = p->pParse; + Window *pMWin = p->pMWin; + Vdbe *v = p->pVdbe; + + int regCRowid = 0; /* Current rowid value */ + int regCPeer = 0; /* Current peer values */ + int regRowid = 0; /* AggStep rowid value */ + int regPeer = 0; /* AggStep peer values */ + + int nPeer; + int lblNext; + int lblBrk; + int addrNext; + int csr; + + VdbeModuleComment((v, "windowFullScan begin")); + + assert( pMWin!=0 ); + csr = pMWin->csrApp; + nPeer = (pMWin->pOrderBy ? pMWin->pOrderBy->nExpr : 0); + + lblNext = sqlite3VdbeMakeLabel(pParse); + lblBrk = sqlite3VdbeMakeLabel(pParse); + + regCRowid = sqlite3GetTempReg(pParse); + regRowid = sqlite3GetTempReg(pParse); + if( nPeer ){ + regCPeer = sqlite3GetTempRange(pParse, nPeer); + regPeer = sqlite3GetTempRange(pParse, nPeer); + } + + sqlite3VdbeAddOp2(v, OP_Rowid, pMWin->iEphCsr, regCRowid); + windowReadPeerValues(p, pMWin->iEphCsr, regCPeer); + + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum); + } + + sqlite3VdbeAddOp3(v, OP_SeekGE, csr, lblBrk, pMWin->regStartRowid); + VdbeCoverage(v); + addrNext = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp2(v, OP_Rowid, csr, regRowid); + sqlite3VdbeAddOp3(v, OP_Gt, pMWin->regEndRowid, lblBrk, regRowid); + VdbeCoverageNeverNull(v); + + if( pMWin->eExclude==TK_CURRENT ){ + sqlite3VdbeAddOp3(v, OP_Eq, regCRowid, lblNext, regRowid); + VdbeCoverageNeverNull(v); + }else if( pMWin->eExclude!=TK_NO ){ + int addr; + int addrEq = 0; + KeyInfo *pKeyInfo = 0; + + if( pMWin->pOrderBy ){ + pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pMWin->pOrderBy, 0, 0); + } + if( pMWin->eExclude==TK_TIES ){ + addrEq = sqlite3VdbeAddOp3(v, OP_Eq, regCRowid, 0, regRowid); + VdbeCoverageNeverNull(v); + } + if( pKeyInfo ){ + windowReadPeerValues(p, csr, regPeer); + sqlite3VdbeAddOp3(v, OP_Compare, regPeer, regCPeer, nPeer); + sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO); + addr = sqlite3VdbeCurrentAddr(v)+1; + sqlite3VdbeAddOp3(v, OP_Jump, addr, lblNext, addr); + VdbeCoverageEqNe(v); + }else{ + sqlite3VdbeAddOp2(v, OP_Goto, 0, lblNext); + } + if( addrEq ) sqlite3VdbeJumpHere(v, addrEq); + } + + windowAggStep(p, pMWin, csr, 0, p->regArg); + + sqlite3VdbeResolveLabel(v, lblNext); + sqlite3VdbeAddOp2(v, OP_Next, csr, addrNext); + VdbeCoverage(v); + sqlite3VdbeJumpHere(v, addrNext-1); + sqlite3VdbeJumpHere(v, addrNext+1); + sqlite3ReleaseTempReg(pParse, regRowid); + sqlite3ReleaseTempReg(pParse, regCRowid); + if( nPeer ){ + sqlite3ReleaseTempRange(pParse, regPeer, nPeer); + sqlite3ReleaseTempRange(pParse, regCPeer, nPeer); + } + + windowAggFinal(p, 1); + VdbeModuleComment((v, "windowFullScan end")); +} + +/* +** Invoke the sub-routine at regGosub (generated by code in select.c) to +** return the current row of Window.iEphCsr. If all window functions are +** aggregate window functions that use the standard API, a single +** OP_Gosub instruction is all that this routine generates. Extra VM code +** for per-row processing is only generated for the following built-in window +** functions: +** +** nth_value() +** first_value() +** lag() +** lead() +*/ +static void windowReturnOneRow(WindowCodeArg *p){ + Window *pMWin = p->pMWin; + Vdbe *v = p->pVdbe; + + if( pMWin->regStartRowid ){ + windowFullScan(p); + }else{ + Parse *pParse = p->pParse; + Window *pWin; + + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + FuncDef *pFunc = pWin->pWFunc; + assert( ExprUseXList(pWin->pOwner) ); + if( pFunc->zName==nth_valueName + || pFunc->zName==first_valueName + ){ + int csr = pWin->csrApp; + int lbl = sqlite3VdbeMakeLabel(pParse); + int tmpReg = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult); + + if( pFunc->zName==nth_valueName ){ + sqlite3VdbeAddOp3(v, OP_Column,pMWin->iEphCsr,pWin->iArgCol+1,tmpReg); + windowCheckValue(pParse, tmpReg, 2); + }else{ + sqlite3VdbeAddOp2(v, OP_Integer, 1, tmpReg); + } + sqlite3VdbeAddOp3(v, OP_Add, tmpReg, pWin->regApp, tmpReg); + sqlite3VdbeAddOp3(v, OP_Gt, pWin->regApp+1, lbl, tmpReg); + VdbeCoverageNeverNull(v); + sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, 0, tmpReg); + VdbeCoverageNeverTaken(v); + sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult); + sqlite3VdbeResolveLabel(v, lbl); + sqlite3ReleaseTempReg(pParse, tmpReg); + } + else if( pFunc->zName==leadName || pFunc->zName==lagName ){ + int nArg = pWin->pOwner->x.pList->nExpr; + int csr = pWin->csrApp; + int lbl = sqlite3VdbeMakeLabel(pParse); + int tmpReg = sqlite3GetTempReg(pParse); + int iEph = pMWin->iEphCsr; + + if( nArg<3 ){ + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult); + }else{ + sqlite3VdbeAddOp3(v, OP_Column, iEph,pWin->iArgCol+2,pWin->regResult); + } + sqlite3VdbeAddOp2(v, OP_Rowid, iEph, tmpReg); + if( nArg<2 ){ + int val = (pFunc->zName==leadName ? 1 : -1); + sqlite3VdbeAddOp2(v, OP_AddImm, tmpReg, val); + }else{ + int op = (pFunc->zName==leadName ? OP_Add : OP_Subtract); + int tmpReg2 = sqlite3GetTempReg(pParse); + sqlite3VdbeAddOp3(v, OP_Column, iEph, pWin->iArgCol+1, tmpReg2); + sqlite3VdbeAddOp3(v, op, tmpReg2, tmpReg, tmpReg); + sqlite3ReleaseTempReg(pParse, tmpReg2); + } + + sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, lbl, tmpReg); + VdbeCoverage(v); + sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult); + sqlite3VdbeResolveLabel(v, lbl); + sqlite3ReleaseTempReg(pParse, tmpReg); + } + } + } + sqlite3VdbeAddOp2(v, OP_Gosub, p->regGosub, p->addrGosub); +} + +/* +** Generate code to set the accumulator register for each window function +** in the linked list passed as the second argument to NULL. And perform +** any equivalent initialization required by any built-in window functions +** in the list. +*/ +static int windowInitAccum(Parse *pParse, Window *pMWin){ + Vdbe *v = sqlite3GetVdbe(pParse); + int regArg; + int nArg = 0; + Window *pWin; + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + FuncDef *pFunc = pWin->pWFunc; + assert( pWin->regAccum ); + sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum); + nArg = MAX(nArg, windowArgCount(pWin)); + if( pMWin->regStartRowid==0 ){ + if( pFunc->zName==nth_valueName || pFunc->zName==first_valueName ){ + sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp); + sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1); + } + + if( (pFunc->funcFlags & SQLITE_FUNC_MINMAX) && pWin->csrApp ){ + assert( pWin->eStart!=TK_UNBOUNDED ); + sqlite3VdbeAddOp1(v, OP_ResetSorter, pWin->csrApp); + sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1); + } + } + } + regArg = pParse->nMem+1; + pParse->nMem += nArg; + return regArg; +} + +/* +** Return true if the current frame should be cached in the ephemeral table, +** even if there are no xInverse() calls required. +*/ +static int windowCacheFrame(Window *pMWin){ + Window *pWin; + if( pMWin->regStartRowid ) return 1; + for(pWin=pMWin; pWin; pWin=pWin->pNextWin){ + FuncDef *pFunc = pWin->pWFunc; + if( (pFunc->zName==nth_valueName) + || (pFunc->zName==first_valueName) + || (pFunc->zName==leadName) + || (pFunc->zName==lagName) + ){ + return 1; + } + } + return 0; +} + +/* +** regOld and regNew are each the first register in an array of size +** pOrderBy->nExpr. This function generates code to compare the two +** arrays of registers using the collation sequences and other comparison +** parameters specified by pOrderBy. +** +** If the two arrays are not equal, the contents of regNew is copied to +** regOld and control falls through. Otherwise, if the contents of the arrays +** are equal, an OP_Goto is executed. The address of the OP_Goto is returned. +*/ +static void windowIfNewPeer( + Parse *pParse, + ExprList *pOrderBy, + int regNew, /* First in array of new values */ + int regOld, /* First in array of old values */ + int addr /* Jump here */ +){ + Vdbe *v = sqlite3GetVdbe(pParse); + if( pOrderBy ){ + int nVal = pOrderBy->nExpr; + KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOrderBy, 0, 0); + sqlite3VdbeAddOp3(v, OP_Compare, regOld, regNew, nVal); + sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO); + sqlite3VdbeAddOp3(v, OP_Jump, + sqlite3VdbeCurrentAddr(v)+1, addr, sqlite3VdbeCurrentAddr(v)+1 + ); + VdbeCoverageEqNe(v); + sqlite3VdbeAddOp3(v, OP_Copy, regNew, regOld, nVal-1); + }else{ + sqlite3VdbeAddOp2(v, OP_Goto, 0, addr); + } +} + +/* +** This function is called as part of generating VM programs for RANGE +** offset PRECEDING/FOLLOWING frame boundaries. Assuming "ASC" order for +** the ORDER BY term in the window, and that argument op is OP_Ge, it generates +** code equivalent to: +** +** if( csr1.peerVal + regVal >= csr2.peerVal ) goto lbl; +** +** The value of parameter op may also be OP_Gt or OP_Le. In these cases the +** operator in the above pseudo-code is replaced with ">" or "<=", respectively. +** +** If the sort-order for the ORDER BY term in the window is DESC, then the +** comparison is reversed. Instead of adding regVal to csr1.peerVal, it is +** subtracted. And the comparison operator is inverted to - ">=" becomes "<=", +** ">" becomes "<", and so on. So, with DESC sort order, if the argument op +** is OP_Ge, the generated code is equivalent to: +** +** if( csr1.peerVal - regVal <= csr2.peerVal ) goto lbl; +** +** A special type of arithmetic is used such that if csr1.peerVal is not +** a numeric type (real or integer), then the result of the addition +** or subtraction is a a copy of csr1.peerVal. +*/ +static void windowCodeRangeTest( + WindowCodeArg *p, + int op, /* OP_Ge, OP_Gt, or OP_Le */ + int csr1, /* Cursor number for cursor 1 */ + int regVal, /* Register containing non-negative number */ + int csr2, /* Cursor number for cursor 2 */ + int lbl /* Jump destination if condition is true */ +){ + Parse *pParse = p->pParse; + Vdbe *v = sqlite3GetVdbe(pParse); + ExprList *pOrderBy = p->pMWin->pOrderBy; /* ORDER BY clause for window */ + int reg1 = sqlite3GetTempReg(pParse); /* Reg. for csr1.peerVal+regVal */ + int reg2 = sqlite3GetTempReg(pParse); /* Reg. for csr2.peerVal */ + int regString = ++pParse->nMem; /* Reg. for constant value '' */ + int arith = OP_Add; /* OP_Add or OP_Subtract */ + int addrGe; /* Jump destination */ + int addrDone = sqlite3VdbeMakeLabel(pParse); /* Address past OP_Ge */ + CollSeq *pColl; + + /* Read the peer-value from each cursor into a register */ + windowReadPeerValues(p, csr1, reg1); + windowReadPeerValues(p, csr2, reg2); + + assert( op==OP_Ge || op==OP_Gt || op==OP_Le ); + assert( pOrderBy && pOrderBy->nExpr==1 ); + if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_DESC ){ + switch( op ){ + case OP_Ge: op = OP_Le; break; + case OP_Gt: op = OP_Lt; break; + default: assert( op==OP_Le ); op = OP_Ge; break; + } + arith = OP_Subtract; + } + + VdbeModuleComment((v, "CodeRangeTest: if( R%d %s R%d %s R%d ) goto lbl", + reg1, (arith==OP_Add ? "+" : "-"), regVal, + ((op==OP_Ge) ? ">=" : (op==OP_Le) ? "<=" : (op==OP_Gt) ? ">" : "<"), reg2 + )); + + /* If the BIGNULL flag is set for the ORDER BY, then it is required to + ** consider NULL values to be larger than all other values, instead of + ** the usual smaller. The VDBE opcodes OP_Ge and so on do not handle this + ** (and adding that capability causes a performance regression), so + ** instead if the BIGNULL flag is set then cases where either reg1 or + ** reg2 are NULL are handled separately in the following block. The code + ** generated is equivalent to: + ** + ** if( reg1 IS NULL ){ + ** if( op==OP_Ge ) goto lbl; + ** if( op==OP_Gt && reg2 IS NOT NULL ) goto lbl; + ** if( op==OP_Le && reg2 IS NULL ) goto lbl; + ** }else if( reg2 IS NULL ){ + ** if( op==OP_Le ) goto lbl; + ** } + ** + ** Additionally, if either reg1 or reg2 are NULL but the jump to lbl is + ** not taken, control jumps over the comparison operator coded below this + ** block. */ + if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_BIGNULL ){ + /* This block runs if reg1 contains a NULL. */ + int addr = sqlite3VdbeAddOp1(v, OP_NotNull, reg1); VdbeCoverage(v); + switch( op ){ + case OP_Ge: + sqlite3VdbeAddOp2(v, OP_Goto, 0, lbl); + break; + case OP_Gt: + sqlite3VdbeAddOp2(v, OP_NotNull, reg2, lbl); + VdbeCoverage(v); + break; + case OP_Le: + sqlite3VdbeAddOp2(v, OP_IsNull, reg2, lbl); + VdbeCoverage(v); + break; + default: assert( op==OP_Lt ); /* no-op */ break; + } + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrDone); + + /* This block runs if reg1 is not NULL, but reg2 is. */ + sqlite3VdbeJumpHere(v, addr); + sqlite3VdbeAddOp2(v, OP_IsNull, reg2, + (op==OP_Gt || op==OP_Ge) ? addrDone : lbl); + VdbeCoverage(v); + } + + /* Register reg1 currently contains csr1.peerVal (the peer-value from csr1). + ** This block adds (or subtracts for DESC) the numeric value in regVal + ** from it. Or, if reg1 is not numeric (it is a NULL, a text value or a blob), + ** then leave reg1 as it is. In pseudo-code, this is implemented as: + ** + ** if( reg1>='' ) goto addrGe; + ** reg1 = reg1 +/- regVal + ** addrGe: + ** + ** Since all strings and blobs are greater-than-or-equal-to an empty string, + ** the add/subtract is skipped for these, as required. If reg1 is a NULL, + ** then the arithmetic is performed, but since adding or subtracting from + ** NULL is always NULL anyway, this case is handled as required too. */ + sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC); + addrGe = sqlite3VdbeAddOp3(v, OP_Ge, regString, 0, reg1); + VdbeCoverage(v); + if( (op==OP_Ge && arith==OP_Add) || (op==OP_Le && arith==OP_Subtract) ){ + sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v); + } + sqlite3VdbeAddOp3(v, arith, regVal, reg1, reg1); + sqlite3VdbeJumpHere(v, addrGe); + + /* Compare registers reg2 and reg1, taking the jump if required. Note that + ** control skips over this test if the BIGNULL flag is set and either + ** reg1 or reg2 contain a NULL value. */ + sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v); + pColl = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[0].pExpr); + sqlite3VdbeAppendP4(v, (void*)pColl, P4_COLLSEQ); + sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); + sqlite3VdbeResolveLabel(v, addrDone); + + assert( op==OP_Ge || op==OP_Gt || op==OP_Lt || op==OP_Le ); + testcase(op==OP_Ge); VdbeCoverageIf(v, op==OP_Ge); + testcase(op==OP_Lt); VdbeCoverageIf(v, op==OP_Lt); + testcase(op==OP_Le); VdbeCoverageIf(v, op==OP_Le); + testcase(op==OP_Gt); VdbeCoverageIf(v, op==OP_Gt); + sqlite3ReleaseTempReg(pParse, reg1); + sqlite3ReleaseTempReg(pParse, reg2); + + VdbeModuleComment((v, "CodeRangeTest: end")); +} + +/* +** Helper function for sqlite3WindowCodeStep(). Each call to this function +** generates VM code for a single RETURN_ROW, AGGSTEP or AGGINVERSE +** operation. Refer to the header comment for sqlite3WindowCodeStep() for +** details. +*/ +static int windowCodeOp( + WindowCodeArg *p, /* Context object */ + int op, /* WINDOW_RETURN_ROW, AGGSTEP or AGGINVERSE */ + int regCountdown, /* Register for OP_IfPos countdown */ + int jumpOnEof /* Jump here if stepped cursor reaches EOF */ +){ + int csr, reg; + Parse *pParse = p->pParse; + Window *pMWin = p->pMWin; + int ret = 0; + Vdbe *v = p->pVdbe; + int addrContinue = 0; + int bPeer = (pMWin->eFrmType!=TK_ROWS); + + int lblDone = sqlite3VdbeMakeLabel(pParse); + int addrNextRange = 0; + + /* Special case - WINDOW_AGGINVERSE is always a no-op if the frame + ** starts with UNBOUNDED PRECEDING. */ + if( op==WINDOW_AGGINVERSE && pMWin->eStart==TK_UNBOUNDED ){ + assert( regCountdown==0 && jumpOnEof==0 ); + return 0; + } + + if( regCountdown>0 ){ + if( pMWin->eFrmType==TK_RANGE ){ + addrNextRange = sqlite3VdbeCurrentAddr(v); + assert( op==WINDOW_AGGINVERSE || op==WINDOW_AGGSTEP ); + if( op==WINDOW_AGGINVERSE ){ + if( pMWin->eStart==TK_FOLLOWING ){ + windowCodeRangeTest( + p, OP_Le, p->current.csr, regCountdown, p->start.csr, lblDone + ); + }else{ + windowCodeRangeTest( + p, OP_Ge, p->start.csr, regCountdown, p->current.csr, lblDone + ); + } + }else{ + windowCodeRangeTest( + p, OP_Gt, p->end.csr, regCountdown, p->current.csr, lblDone + ); + } + }else{ + sqlite3VdbeAddOp3(v, OP_IfPos, regCountdown, lblDone, 1); + VdbeCoverage(v); + } + } + + if( op==WINDOW_RETURN_ROW && pMWin->regStartRowid==0 ){ + windowAggFinal(p, 0); + } + addrContinue = sqlite3VdbeCurrentAddr(v); + + /* If this is a (RANGE BETWEEN a FOLLOWING AND b FOLLOWING) or + ** (RANGE BETWEEN b PRECEDING AND a PRECEDING) frame, ensure the + ** start cursor does not advance past the end cursor within the + ** temporary table. It otherwise might, if (a>b). Also ensure that, + ** if the input cursor is still finding new rows, that the end + ** cursor does not go past it to EOF. */ + if( pMWin->eStart==pMWin->eEnd && regCountdown + && pMWin->eFrmType==TK_RANGE + ){ + int regRowid1 = sqlite3GetTempReg(pParse); + int regRowid2 = sqlite3GetTempReg(pParse); + if( op==WINDOW_AGGINVERSE ){ + sqlite3VdbeAddOp2(v, OP_Rowid, p->start.csr, regRowid1); + sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid2); + sqlite3VdbeAddOp3(v, OP_Ge, regRowid2, lblDone, regRowid1); + VdbeCoverage(v); + }else if( p->regRowid ){ + sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid1); + sqlite3VdbeAddOp3(v, OP_Ge, p->regRowid, lblDone, regRowid1); + VdbeCoverageNeverNull(v); + } + sqlite3ReleaseTempReg(pParse, regRowid1); + sqlite3ReleaseTempReg(pParse, regRowid2); + assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING ); + } + + switch( op ){ + case WINDOW_RETURN_ROW: + csr = p->current.csr; + reg = p->current.reg; + windowReturnOneRow(p); + break; + + case WINDOW_AGGINVERSE: + csr = p->start.csr; + reg = p->start.reg; + if( pMWin->regStartRowid ){ + assert( pMWin->regEndRowid ); + sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regStartRowid, 1); + }else{ + windowAggStep(p, pMWin, csr, 1, p->regArg); + } + break; + + default: + assert( op==WINDOW_AGGSTEP ); + csr = p->end.csr; + reg = p->end.reg; + if( pMWin->regStartRowid ){ + assert( pMWin->regEndRowid ); + sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regEndRowid, 1); + }else{ + windowAggStep(p, pMWin, csr, 0, p->regArg); + } + break; + } + + if( op==p->eDelete ){ + sqlite3VdbeAddOp1(v, OP_Delete, csr); + sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION); + } + + if( jumpOnEof ){ + sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+2); + VdbeCoverage(v); + ret = sqlite3VdbeAddOp0(v, OP_Goto); + }else{ + sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+1+bPeer); + VdbeCoverage(v); + if( bPeer ){ + sqlite3VdbeAddOp2(v, OP_Goto, 0, lblDone); + } + } + + if( bPeer ){ + int nReg = (pMWin->pOrderBy ? pMWin->pOrderBy->nExpr : 0); + int regTmp = (nReg ? sqlite3GetTempRange(pParse, nReg) : 0); + windowReadPeerValues(p, csr, regTmp); + windowIfNewPeer(pParse, pMWin->pOrderBy, regTmp, reg, addrContinue); + sqlite3ReleaseTempRange(pParse, regTmp, nReg); + } + + if( addrNextRange ){ + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrNextRange); + } + sqlite3VdbeResolveLabel(v, lblDone); + return ret; +} + + +/* +** Allocate and return a duplicate of the Window object indicated by the +** third argument. Set the Window.pOwner field of the new object to +** pOwner. +*/ +Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p){ + Window *pNew = 0; + if( ALWAYS(p) ){ + pNew = sqlite3DbMallocZero(db, sizeof(Window)); + if( pNew ){ + pNew->zName = sqlite3DbStrDup(db, p->zName); + pNew->zBase = sqlite3DbStrDup(db, p->zBase); + pNew->pFilter = sqlite3ExprDup(db, p->pFilter, 0); + pNew->pWFunc = p->pWFunc; + pNew->pPartition = sqlite3ExprListDup(db, p->pPartition, 0); + pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, 0); + pNew->eFrmType = p->eFrmType; + pNew->eEnd = p->eEnd; + pNew->eStart = p->eStart; + pNew->eExclude = p->eExclude; + pNew->regResult = p->regResult; + pNew->regAccum = p->regAccum; + pNew->iArgCol = p->iArgCol; + pNew->iEphCsr = p->iEphCsr; + pNew->bExprArgs = p->bExprArgs; + pNew->pStart = sqlite3ExprDup(db, p->pStart, 0); + pNew->pEnd = sqlite3ExprDup(db, p->pEnd, 0); + pNew->pOwner = pOwner; + pNew->bImplicitFrame = p->bImplicitFrame; + } + } + return pNew; +} + +/* +** Return a copy of the linked list of Window objects passed as the +** second argument. +*/ +Window *sqlite3WindowListDup(sqlite3 *db, Window *p){ + Window *pWin; + Window *pRet = 0; + Window **pp = &pRet; + + for(pWin=p; pWin; pWin=pWin->pNextWin){ + *pp = sqlite3WindowDup(db, 0, pWin); + if( *pp==0 ) break; + pp = &((*pp)->pNextWin); + } + + return pRet; +} + +/* +** Return true if it can be determined at compile time that expression +** pExpr evaluates to a value that, when cast to an integer, is greater +** than zero. False otherwise. +** +** If an OOM error occurs, this function sets the Parse.db.mallocFailed +** flag and returns zero. +*/ +static int windowExprGtZero(Parse *pParse, Expr *pExpr){ + int ret = 0; + sqlite3 *db = pParse->db; + sqlite3_value *pVal = 0; + sqlite3ValueFromExpr(db, pExpr, db->enc, SQLITE_AFF_NUMERIC, &pVal); + if( pVal && sqlite3_value_int(pVal)>0 ){ + ret = 1; + } + sqlite3ValueFree(pVal); + return ret; +} + +/* +** sqlite3WhereBegin() has already been called for the SELECT statement +** passed as the second argument when this function is invoked. It generates +** code to populate the Window.regResult register for each window function +** and invoke the sub-routine at instruction addrGosub once for each row. +** sqlite3WhereEnd() is always called before returning. +** +** This function handles several different types of window frames, which +** require slightly different processing. The following pseudo code is +** used to implement window frames of the form: +** +** ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING +** +** Other window frame types use variants of the following: +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** +** if( first row of partition ){ +** // Rewind three cursors, all open on the eph table. +** Rewind(csrEnd); +** Rewind(csrStart); +** Rewind(csrCurrent); +** +** regEnd = <expr2> // FOLLOWING expression +** regStart = <expr1> // PRECEDING expression +** }else{ +** // First time this branch is taken, the eph table contains two +** // rows. The first row in the partition, which all three cursors +** // currently point to, and the following row. +** AGGSTEP +** if( (regEnd--)<=0 ){ +** RETURN_ROW +** if( (regStart--)<=0 ){ +** AGGINVERSE +** } +** } +** } +** } +** flush: +** AGGSTEP +** while( 1 ){ +** RETURN ROW +** if( csrCurrent is EOF ) break; +** if( (regStart--)<=0 ){ +** AggInverse(csrStart) +** Next(csrStart) +** } +** } +** +** The pseudo-code above uses the following shorthand: +** +** AGGSTEP: invoke the aggregate xStep() function for each window function +** with arguments read from the current row of cursor csrEnd, then +** step cursor csrEnd forward one row (i.e. sqlite3BtreeNext()). +** +** RETURN_ROW: return a row to the caller based on the contents of the +** current row of csrCurrent and the current state of all +** aggregates. Then step cursor csrCurrent forward one row. +** +** AGGINVERSE: invoke the aggregate xInverse() function for each window +** functions with arguments read from the current row of cursor +** csrStart. Then step csrStart forward one row. +** +** There are two other ROWS window frames that are handled significantly +** differently from the above - "BETWEEN <expr> PRECEDING AND <expr> PRECEDING" +** and "BETWEEN <expr> FOLLOWING AND <expr> FOLLOWING". These are special +** cases because they change the order in which the three cursors (csrStart, +** csrCurrent and csrEnd) iterate through the ephemeral table. Cases that +** use UNBOUNDED or CURRENT ROW are much simpler variations on one of these +** three. +** +** ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = <expr1> +** }else{ +** if( (regEnd--)<=0 ){ +** AGGSTEP +** } +** RETURN_ROW +** if( (regStart--)<=0 ){ +** AGGINVERSE +** } +** } +** } +** flush: +** if( (regEnd--)<=0 ){ +** AGGSTEP +** } +** RETURN_ROW +** +** +** ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = regEnd - <expr1> +** }else{ +** AGGSTEP +** if( (regEnd--)<=0 ){ +** RETURN_ROW +** } +** if( (regStart--)<=0 ){ +** AGGINVERSE +** } +** } +** } +** flush: +** AGGSTEP +** while( 1 ){ +** if( (regEnd--)<=0 ){ +** RETURN_ROW +** if( eof ) break; +** } +** if( (regStart--)<=0 ){ +** AGGINVERSE +** if( eof ) break +** } +** } +** while( !eof csrCurrent ){ +** RETURN_ROW +** } +** +** For the most part, the patterns above are adapted to support UNBOUNDED by +** assuming that it is equivalent to "infinity PRECEDING/FOLLOWING" and +** CURRENT ROW by assuming that it is equivilent to "0 PRECEDING/FOLLOWING". +** This is optimized of course - branches that will never be taken and +** conditions that are always true are omitted from the VM code. The only +** exceptional case is: +** +** ROWS BETWEEN <expr1> FOLLOWING AND UNBOUNDED FOLLOWING +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regStart = <expr1> +** }else{ +** AGGSTEP +** } +** } +** flush: +** AGGSTEP +** while( 1 ){ +** if( (regStart--)<=0 ){ +** AGGINVERSE +** if( eof ) break +** } +** RETURN_ROW +** } +** while( !eof csrCurrent ){ +** RETURN_ROW +** } +** +** Also requiring special handling are the cases: +** +** ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING +** ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING +** +** when (expr1 < expr2). This is detected at runtime, not by this function. +** To handle this case, the pseudo-code programs depicted above are modified +** slightly to be: +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = <expr1> +** if( regEnd < regStart ){ +** RETURN_ROW +** delete eph table contents +** continue +** } +** ... +** +** The new "continue" statement in the above jumps to the next iteration +** of the outer loop - the one started by sqlite3WhereBegin(). +** +** The various GROUPS cases are implemented using the same patterns as +** ROWS. The VM code is modified slightly so that: +** +** 1. The else branch in the main loop is only taken if the row just +** added to the ephemeral table is the start of a new group. In +** other words, it becomes: +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = <expr1> +** }else if( new group ){ +** ... +** } +** } +** +** 2. Instead of processing a single row, each RETURN_ROW, AGGSTEP or +** AGGINVERSE step processes the current row of the relevant cursor and +** all subsequent rows belonging to the same group. +** +** RANGE window frames are a little different again. As for GROUPS, the +** main loop runs once per group only. And RETURN_ROW, AGGSTEP and AGGINVERSE +** deal in groups instead of rows. As for ROWS and GROUPS, there are three +** basic cases: +** +** RANGE BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = <expr1> +** }else{ +** AGGSTEP +** while( (csrCurrent.key + regEnd) < csrEnd.key ){ +** RETURN_ROW +** while( csrStart.key + regStart) < csrCurrent.key ){ +** AGGINVERSE +** } +** } +** } +** } +** flush: +** AGGSTEP +** while( 1 ){ +** RETURN ROW +** if( csrCurrent is EOF ) break; +** while( csrStart.key + regStart) < csrCurrent.key ){ +** AGGINVERSE +** } +** } +** } +** +** In the above notation, "csr.key" means the current value of the ORDER BY +** expression (there is only ever 1 for a RANGE that uses an <expr> FOLLOWING +** or <expr PRECEDING) read from cursor csr. +** +** RANGE BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = <expr1> +** }else{ +** while( (csrEnd.key + regEnd) <= csrCurrent.key ){ +** AGGSTEP +** } +** while( (csrStart.key + regStart) < csrCurrent.key ){ +** AGGINVERSE +** } +** RETURN_ROW +** } +** } +** flush: +** while( (csrEnd.key + regEnd) <= csrCurrent.key ){ +** AGGSTEP +** } +** while( (csrStart.key + regStart) < csrCurrent.key ){ +** AGGINVERSE +** } +** RETURN_ROW +** +** RANGE BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING +** +** ... loop started by sqlite3WhereBegin() ... +** if( new partition ){ +** Gosub flush +** } +** Insert new row into eph table. +** if( first row of partition ){ +** Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent) +** regEnd = <expr2> +** regStart = <expr1> +** }else{ +** AGGSTEP +** while( (csrCurrent.key + regEnd) < csrEnd.key ){ +** while( (csrCurrent.key + regStart) > csrStart.key ){ +** AGGINVERSE +** } +** RETURN_ROW +** } +** } +** } +** flush: +** AGGSTEP +** while( 1 ){ +** while( (csrCurrent.key + regStart) > csrStart.key ){ +** AGGINVERSE +** if( eof ) break "while( 1 )" loop. +** } +** RETURN_ROW +** } +** while( !eof csrCurrent ){ +** RETURN_ROW +** } +** +** The text above leaves out many details. Refer to the code and comments +** below for a more complete picture. +*/ +void sqlite3WindowCodeStep( + Parse *pParse, /* Parse context */ + Select *p, /* Rewritten SELECT statement */ + WhereInfo *pWInfo, /* Context returned by sqlite3WhereBegin() */ + int regGosub, /* Register for OP_Gosub */ + int addrGosub /* OP_Gosub here to return each row */ +){ + Window *pMWin = p->pWin; + ExprList *pOrderBy = pMWin->pOrderBy; + Vdbe *v = sqlite3GetVdbe(pParse); + int csrWrite; /* Cursor used to write to eph. table */ + int csrInput = p->pSrc->a[0].iCursor; /* Cursor of sub-select */ + int nInput = p->pSrc->a[0].pTab->nCol; /* Number of cols returned by sub */ + int iInput; /* To iterate through sub cols */ + int addrNe; /* Address of OP_Ne */ + int addrGosubFlush = 0; /* Address of OP_Gosub to flush: */ + int addrInteger = 0; /* Address of OP_Integer */ + int addrEmpty; /* Address of OP_Rewind in flush: */ + int regNew; /* Array of registers holding new input row */ + int regRecord; /* regNew array in record form */ + int regNewPeer = 0; /* Peer values for new row (part of regNew) */ + int regPeer = 0; /* Peer values for current row */ + int regFlushPart = 0; /* Register for "Gosub flush_partition" */ + WindowCodeArg s; /* Context object for sub-routines */ + int lblWhereEnd; /* Label just before sqlite3WhereEnd() code */ + int regStart = 0; /* Value of <expr> PRECEDING */ + int regEnd = 0; /* Value of <expr> FOLLOWING */ + + assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_CURRENT + || pMWin->eStart==TK_FOLLOWING || pMWin->eStart==TK_UNBOUNDED + ); + assert( pMWin->eEnd==TK_FOLLOWING || pMWin->eEnd==TK_CURRENT + || pMWin->eEnd==TK_UNBOUNDED || pMWin->eEnd==TK_PRECEDING + ); + assert( pMWin->eExclude==0 || pMWin->eExclude==TK_CURRENT + || pMWin->eExclude==TK_GROUP || pMWin->eExclude==TK_TIES + || pMWin->eExclude==TK_NO + ); + + lblWhereEnd = sqlite3VdbeMakeLabel(pParse); + + /* Fill in the context object */ + memset(&s, 0, sizeof(WindowCodeArg)); + s.pParse = pParse; + s.pMWin = pMWin; + s.pVdbe = v; + s.regGosub = regGosub; + s.addrGosub = addrGosub; + s.current.csr = pMWin->iEphCsr; + csrWrite = s.current.csr+1; + s.start.csr = s.current.csr+2; + s.end.csr = s.current.csr+3; + + /* Figure out when rows may be deleted from the ephemeral table. There + ** are four options - they may never be deleted (eDelete==0), they may + ** be deleted as soon as they are no longer part of the window frame + ** (eDelete==WINDOW_AGGINVERSE), they may be deleted as after the row + ** has been returned to the caller (WINDOW_RETURN_ROW), or they may + ** be deleted after they enter the frame (WINDOW_AGGSTEP). */ + switch( pMWin->eStart ){ + case TK_FOLLOWING: + if( pMWin->eFrmType!=TK_RANGE + && windowExprGtZero(pParse, pMWin->pStart) + ){ + s.eDelete = WINDOW_RETURN_ROW; + } + break; + case TK_UNBOUNDED: + if( windowCacheFrame(pMWin)==0 ){ + if( pMWin->eEnd==TK_PRECEDING ){ + if( pMWin->eFrmType!=TK_RANGE + && windowExprGtZero(pParse, pMWin->pEnd) + ){ + s.eDelete = WINDOW_AGGSTEP; + } + }else{ + s.eDelete = WINDOW_RETURN_ROW; + } + } + break; + default: + s.eDelete = WINDOW_AGGINVERSE; + break; + } + + /* Allocate registers for the array of values from the sub-query, the + ** samve values in record form, and the rowid used to insert said record + ** into the ephemeral table. */ + regNew = pParse->nMem+1; + pParse->nMem += nInput; + regRecord = ++pParse->nMem; + s.regRowid = ++pParse->nMem; + + /* If the window frame contains an "<expr> PRECEDING" or "<expr> FOLLOWING" + ** clause, allocate registers to store the results of evaluating each + ** <expr>. */ + if( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING ){ + regStart = ++pParse->nMem; + } + if( pMWin->eEnd==TK_PRECEDING || pMWin->eEnd==TK_FOLLOWING ){ + regEnd = ++pParse->nMem; + } + + /* If this is not a "ROWS BETWEEN ..." frame, then allocate arrays of + ** registers to store copies of the ORDER BY expressions (peer values) + ** for the main loop, and for each cursor (start, current and end). */ + if( pMWin->eFrmType!=TK_ROWS ){ + int nPeer = (pOrderBy ? pOrderBy->nExpr : 0); + regNewPeer = regNew + pMWin->nBufferCol; + if( pMWin->pPartition ) regNewPeer += pMWin->pPartition->nExpr; + regPeer = pParse->nMem+1; pParse->nMem += nPeer; + s.start.reg = pParse->nMem+1; pParse->nMem += nPeer; + s.current.reg = pParse->nMem+1; pParse->nMem += nPeer; + s.end.reg = pParse->nMem+1; pParse->nMem += nPeer; + } + + /* Load the column values for the row returned by the sub-select + ** into an array of registers starting at regNew. Assemble them into + ** a record in register regRecord. */ + for(iInput=0; iInput<nInput; iInput++){ + sqlite3VdbeAddOp3(v, OP_Column, csrInput, iInput, regNew+iInput); + } + sqlite3VdbeAddOp3(v, OP_MakeRecord, regNew, nInput, regRecord); + + /* An input row has just been read into an array of registers starting + ** at regNew. If the window has a PARTITION clause, this block generates + ** VM code to check if the input row is the start of a new partition. + ** If so, it does an OP_Gosub to an address to be filled in later. The + ** address of the OP_Gosub is stored in local variable addrGosubFlush. */ + if( pMWin->pPartition ){ + int addr; + ExprList *pPart = pMWin->pPartition; + int nPart = pPart->nExpr; + int regNewPart = regNew + pMWin->nBufferCol; + KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0); + + regFlushPart = ++pParse->nMem; + addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart, nPart); + sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO); + sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2); + VdbeCoverageEqNe(v); + addrGosubFlush = sqlite3VdbeAddOp1(v, OP_Gosub, regFlushPart); + VdbeComment((v, "call flush_partition")); + sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart-1); + } + + /* Insert the new row into the ephemeral table */ + sqlite3VdbeAddOp2(v, OP_NewRowid, csrWrite, s.regRowid); + sqlite3VdbeAddOp3(v, OP_Insert, csrWrite, regRecord, s.regRowid); + addrNe = sqlite3VdbeAddOp3(v, OP_Ne, pMWin->regOne, 0, s.regRowid); + VdbeCoverageNeverNull(v); + + /* This block is run for the first row of each partition */ + s.regArg = windowInitAccum(pParse, pMWin); + + if( regStart ){ + sqlite3ExprCode(pParse, pMWin->pStart, regStart); + windowCheckValue(pParse, regStart, 0 + (pMWin->eFrmType==TK_RANGE?3:0)); + } + if( regEnd ){ + sqlite3ExprCode(pParse, pMWin->pEnd, regEnd); + windowCheckValue(pParse, regEnd, 1 + (pMWin->eFrmType==TK_RANGE?3:0)); + } + + if( pMWin->eFrmType!=TK_RANGE && pMWin->eStart==pMWin->eEnd && regStart ){ + int op = ((pMWin->eStart==TK_FOLLOWING) ? OP_Ge : OP_Le); + int addrGe = sqlite3VdbeAddOp3(v, op, regStart, 0, regEnd); + VdbeCoverageNeverNullIf(v, op==OP_Ge); /* NeverNull because bound <expr> */ + VdbeCoverageNeverNullIf(v, op==OP_Le); /* values previously checked */ + windowAggFinal(&s, 0); + sqlite3VdbeAddOp2(v, OP_Rewind, s.current.csr, 1); + VdbeCoverageNeverTaken(v); + windowReturnOneRow(&s); + sqlite3VdbeAddOp1(v, OP_ResetSorter, s.current.csr); + sqlite3VdbeAddOp2(v, OP_Goto, 0, lblWhereEnd); + sqlite3VdbeJumpHere(v, addrGe); + } + if( pMWin->eStart==TK_FOLLOWING && pMWin->eFrmType!=TK_RANGE && regEnd ){ + assert( pMWin->eEnd==TK_FOLLOWING ); + sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regStart); + } + + if( pMWin->eStart!=TK_UNBOUNDED ){ + sqlite3VdbeAddOp2(v, OP_Rewind, s.start.csr, 1); + VdbeCoverageNeverTaken(v); + } + sqlite3VdbeAddOp2(v, OP_Rewind, s.current.csr, 1); + VdbeCoverageNeverTaken(v); + sqlite3VdbeAddOp2(v, OP_Rewind, s.end.csr, 1); + VdbeCoverageNeverTaken(v); + if( regPeer && pOrderBy ){ + sqlite3VdbeAddOp3(v, OP_Copy, regNewPeer, regPeer, pOrderBy->nExpr-1); + sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.start.reg, pOrderBy->nExpr-1); + sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.current.reg, pOrderBy->nExpr-1); + sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.end.reg, pOrderBy->nExpr-1); + } + + sqlite3VdbeAddOp2(v, OP_Goto, 0, lblWhereEnd); + + sqlite3VdbeJumpHere(v, addrNe); + + /* Beginning of the block executed for the second and subsequent rows. */ + if( regPeer ){ + windowIfNewPeer(pParse, pOrderBy, regNewPeer, regPeer, lblWhereEnd); + } + if( pMWin->eStart==TK_FOLLOWING ){ + windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0); + if( pMWin->eEnd!=TK_UNBOUNDED ){ + if( pMWin->eFrmType==TK_RANGE ){ + int lbl = sqlite3VdbeMakeLabel(pParse); + int addrNext = sqlite3VdbeCurrentAddr(v); + windowCodeRangeTest(&s, OP_Ge, s.current.csr, regEnd, s.end.csr, lbl); + windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0); + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrNext); + sqlite3VdbeResolveLabel(v, lbl); + }else{ + windowCodeOp(&s, WINDOW_RETURN_ROW, regEnd, 0); + windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + } + } + }else + if( pMWin->eEnd==TK_PRECEDING ){ + int bRPS = (pMWin->eStart==TK_PRECEDING && pMWin->eFrmType==TK_RANGE); + windowCodeOp(&s, WINDOW_AGGSTEP, regEnd, 0); + if( bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0); + if( !bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + }else{ + int addr = 0; + windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0); + if( pMWin->eEnd!=TK_UNBOUNDED ){ + if( pMWin->eFrmType==TK_RANGE ){ + int lbl = 0; + addr = sqlite3VdbeCurrentAddr(v); + if( regEnd ){ + lbl = sqlite3VdbeMakeLabel(pParse); + windowCodeRangeTest(&s, OP_Ge, s.current.csr, regEnd, s.end.csr, lbl); + } + windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0); + windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + if( regEnd ){ + sqlite3VdbeAddOp2(v, OP_Goto, 0, addr); + sqlite3VdbeResolveLabel(v, lbl); + } + }else{ + if( regEnd ){ + addr = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1); + VdbeCoverage(v); + } + windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0); + windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + if( regEnd ) sqlite3VdbeJumpHere(v, addr); + } + } + } + + /* End of the main input loop */ + sqlite3VdbeResolveLabel(v, lblWhereEnd); + sqlite3WhereEnd(pWInfo); + + /* Fall through */ + if( pMWin->pPartition ){ + addrInteger = sqlite3VdbeAddOp2(v, OP_Integer, 0, regFlushPart); + sqlite3VdbeJumpHere(v, addrGosubFlush); + } + + s.regRowid = 0; + addrEmpty = sqlite3VdbeAddOp1(v, OP_Rewind, csrWrite); + VdbeCoverage(v); + if( pMWin->eEnd==TK_PRECEDING ){ + int bRPS = (pMWin->eStart==TK_PRECEDING && pMWin->eFrmType==TK_RANGE); + windowCodeOp(&s, WINDOW_AGGSTEP, regEnd, 0); + if( bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0); + }else if( pMWin->eStart==TK_FOLLOWING ){ + int addrStart; + int addrBreak1; + int addrBreak2; + int addrBreak3; + windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0); + if( pMWin->eFrmType==TK_RANGE ){ + addrStart = sqlite3VdbeCurrentAddr(v); + addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 1); + addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1); + }else + if( pMWin->eEnd==TK_UNBOUNDED ){ + addrStart = sqlite3VdbeCurrentAddr(v); + addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, regStart, 1); + addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, 0, 1); + }else{ + assert( pMWin->eEnd==TK_FOLLOWING ); + addrStart = sqlite3VdbeCurrentAddr(v); + addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, regEnd, 1); + addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 1); + } + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart); + sqlite3VdbeJumpHere(v, addrBreak2); + addrStart = sqlite3VdbeCurrentAddr(v); + addrBreak3 = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1); + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart); + sqlite3VdbeJumpHere(v, addrBreak1); + sqlite3VdbeJumpHere(v, addrBreak3); + }else{ + int addrBreak; + int addrStart; + windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0); + addrStart = sqlite3VdbeCurrentAddr(v); + addrBreak = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1); + windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0); + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart); + sqlite3VdbeJumpHere(v, addrBreak); + } + sqlite3VdbeJumpHere(v, addrEmpty); + + sqlite3VdbeAddOp1(v, OP_ResetSorter, s.current.csr); + if( pMWin->pPartition ){ + if( pMWin->regStartRowid ){ + sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid); + sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid); + } + sqlite3VdbeChangeP1(v, addrInteger, sqlite3VdbeCurrentAddr(v)); + sqlite3VdbeAddOp1(v, OP_Return, regFlushPart); + } +} + +#endif /* SQLITE_OMIT_WINDOWFUNC */ |