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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 18:07:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 18:07:14 +0000
commita175314c3e5827eb193872241446f2f8f5c9d33c (patch)
treecd3d60ca99ae00829c52a6ca79150a5b6e62528b /sql/item_windowfunc.h
parentInitial commit. (diff)
downloadmariadb-10.5-a175314c3e5827eb193872241446f2f8f5c9d33c.tar.xz
mariadb-10.5-a175314c3e5827eb193872241446f2f8f5c9d33c.zip
Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--sql/item_windowfunc.h1372
1 files changed, 1372 insertions, 0 deletions
diff --git a/sql/item_windowfunc.h b/sql/item_windowfunc.h
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@@ -0,0 +1,1372 @@
+/*
+ Copyright (c) 2016, 2020, MariaDB
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 of the License.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
+
+#ifndef ITEM_WINDOWFUNC_INCLUDED
+#define ITEM_WINDOWFUNC_INCLUDED
+
+#include "item.h"
+
+class Window_spec;
+
+
+int test_if_group_changed(List<Cached_item> &list);
+
+
+/* A wrapper around test_if_group_changed */
+class Group_bound_tracker
+{
+public:
+
+ Group_bound_tracker(THD *thd, SQL_I_List<ORDER> *list)
+ {
+ for (ORDER *curr = list->first; curr; curr=curr->next)
+ {
+ Cached_item *tmp= new_Cached_item(thd, curr->item[0], TRUE);
+ group_fields.push_back(tmp);
+ }
+ }
+
+ void init()
+ {
+ first_check= true;
+ }
+
+ /*
+ Check if the current row is in a different group than the previous row
+ this function was called for.
+ XXX: Side-effect: The new row's group becomes the current row's group.
+
+ Returns true if there is a change between the current_group and the cached
+ value, or if it is the first check after a call to init.
+ */
+ bool check_if_next_group()
+ {
+ if (test_if_group_changed(group_fields) > -1 || first_check)
+ {
+ first_check= false;
+ return true;
+ }
+ return false;
+ }
+
+ /*
+ Check if the current row is in a different group than the previous row
+ check_if_next_group was called for.
+
+ Compares the groups without the additional side effect of updating the
+ current cached values.
+ */
+ int compare_with_cache()
+ {
+ List_iterator<Cached_item> li(group_fields);
+ Cached_item *ptr;
+ int res;
+ while ((ptr= li++))
+ {
+ if ((res= ptr->cmp_read_only()))
+ return res;
+ }
+ return 0;
+ }
+ ~Group_bound_tracker()
+ {
+ group_fields.delete_elements();
+ }
+
+private:
+ List<Cached_item> group_fields;
+ /*
+ During the first check_if_next_group, the list of cached_items is not
+ initialized. The compare function will return that the items match if
+ the field's value is the same as the Cached_item's default value (0).
+ This flag makes sure that we always return true during the first check.
+
+ XXX This is better to be implemented within test_if_group_changed, but
+ since it is used in other parts of the codebase, we keep it here for now.
+ */
+ bool first_check;
+};
+
+/*
+ ROW_NUMBER() OVER (...)
+
+ @detail
+ - This is a Window function (not just an aggregate)
+ - It can be computed by doing one pass over select output, provided
+ the output is sorted according to the window definition.
+*/
+
+class Item_sum_row_number: public Item_sum_int
+{
+ longlong count;
+
+public:
+
+ Item_sum_row_number(THD *thd)
+ : Item_sum_int(thd), count(0) {}
+
+ const Type_handler *type_handler() const { return &type_handler_slonglong; }
+
+ void clear()
+ {
+ count= 0;
+ }
+
+ bool add()
+ {
+ count++;
+ return false;
+ }
+
+ void reset_field() { DBUG_ASSERT(0); }
+ void update_field() {}
+
+ enum Sumfunctype sum_func() const
+ {
+ return ROW_NUMBER_FUNC;
+ }
+
+ longlong val_int()
+ {
+ return count;
+ }
+ const char*func_name() const
+ {
+ return "row_number";
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_row_number>(thd, this); }
+};
+
+
+/*
+ RANK() OVER (...) Windowing function
+
+ @detail
+ - This is a Window function (not just an aggregate)
+ - It can be computed by doing one pass over select output, provided
+ the output is sorted according to the window definition.
+
+ The function is defined as:
+
+ "The rank of row R is defined as 1 (one) plus the number of rows that
+ precede R and are not peers of R"
+
+ "This implies that if two or more rows are not distinct with respect to
+ the window ordering, then there will be one or more"
+*/
+
+class Item_sum_rank: public Item_sum_int
+{
+protected:
+ longlong row_number; // just ROW_NUMBER()
+ longlong cur_rank; // current value
+
+ Group_bound_tracker *peer_tracker;
+public:
+
+ Item_sum_rank(THD *thd) : Item_sum_int(thd), peer_tracker(NULL) {}
+
+ const Type_handler *type_handler() const { return &type_handler_slonglong; }
+
+ void clear()
+ {
+ /* This is called on partition start */
+ cur_rank= 1;
+ row_number= 0;
+ }
+
+ bool add();
+
+ longlong val_int()
+ {
+ return cur_rank;
+ }
+
+ void reset_field() { DBUG_ASSERT(0); }
+ void update_field() {}
+
+ enum Sumfunctype sum_func () const
+ {
+ return RANK_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "rank";
+ }
+
+ void setup_window_func(THD *thd, Window_spec *window_spec);
+
+ void cleanup()
+ {
+ if (peer_tracker)
+ {
+ delete peer_tracker;
+ peer_tracker= NULL;
+ }
+ Item_sum_int::cleanup();
+ }
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_rank>(thd, this); }
+};
+
+
+/*
+ DENSE_RANK() OVER (...) Windowing function
+
+ @detail
+ - This is a Window function (not just an aggregate)
+ - It can be computed by doing one pass over select output, provided
+ the output is sorted according to the window definition.
+
+ The function is defined as:
+
+ "If DENSE_RANK is specified, then the rank of row R is defined as the
+ number of rows preceding and including R that are distinct with respect
+ to the window ordering"
+
+ "This implies that there are no gaps in the sequential rank numbering of
+ rows in each window partition."
+*/
+
+
+class Item_sum_dense_rank: public Item_sum_int
+{
+ longlong dense_rank;
+ bool first_add;
+ Group_bound_tracker *peer_tracker;
+ public:
+ /*
+ XXX(cvicentiu) This class could potentially be implemented in the rank
+ class, with a switch for the DENSE case.
+ */
+ void clear()
+ {
+ dense_rank= 0;
+ first_add= true;
+ }
+ bool add();
+ void reset_field() { DBUG_ASSERT(0); }
+ void update_field() {}
+ longlong val_int()
+ {
+ return dense_rank;
+ }
+
+ Item_sum_dense_rank(THD *thd)
+ : Item_sum_int(thd), dense_rank(0), first_add(true), peer_tracker(NULL) {}
+ const Type_handler *type_handler() const { return &type_handler_slonglong; }
+ enum Sumfunctype sum_func () const
+ {
+ return DENSE_RANK_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "dense_rank";
+ }
+
+ void setup_window_func(THD *thd, Window_spec *window_spec);
+
+ void cleanup()
+ {
+ if (peer_tracker)
+ {
+ delete peer_tracker;
+ peer_tracker= NULL;
+ }
+ Item_sum_int::cleanup();
+ }
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_dense_rank>(thd, this); }
+};
+
+class Item_sum_hybrid_simple : public Item_sum_hybrid
+{
+ public:
+ Item_sum_hybrid_simple(THD *thd, Item *arg):
+ Item_sum_hybrid(thd, arg),
+ value(NULL)
+ { }
+
+ Item_sum_hybrid_simple(THD *thd, Item *arg1, Item *arg2):
+ Item_sum_hybrid(thd, arg1, arg2),
+ value(NULL)
+ { }
+
+ bool add();
+ bool fix_fields(THD *, Item **);
+ bool fix_length_and_dec();
+ void setup_hybrid(THD *thd, Item *item);
+ double val_real();
+ longlong val_int();
+ my_decimal *val_decimal(my_decimal *);
+ void reset_field();
+ String *val_str(String *);
+ bool val_native(THD *thd, Native *to);
+ bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate);
+ const Type_handler *type_handler() const
+ { return Type_handler_hybrid_field_type::type_handler(); }
+ void update_field();
+ Field *create_tmp_field(MEM_ROOT *root, bool group, TABLE *table);
+ void clear()
+ {
+ value->clear();
+ null_value= 1;
+ }
+
+ private:
+ Item_cache *value;
+};
+
+/*
+ This item will remember the first value added to it. It will not update
+ the value unless it is cleared.
+*/
+class Item_sum_first_value : public Item_sum_hybrid_simple
+{
+ public:
+ Item_sum_first_value(THD* thd, Item* arg_expr) :
+ Item_sum_hybrid_simple(thd, arg_expr) {}
+
+
+ enum Sumfunctype sum_func () const
+ {
+ return FIRST_VALUE_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "first_value";
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_first_value>(thd, this); }
+};
+
+/*
+ This item will remember the last value added to it.
+
+ This item does not support removal, and can be cleared only by calling
+ clear().
+*/
+class Item_sum_last_value : public Item_sum_hybrid_simple
+{
+ public:
+ Item_sum_last_value(THD* thd, Item* arg_expr) :
+ Item_sum_hybrid_simple(thd, arg_expr) {}
+
+ enum Sumfunctype sum_func() const
+ {
+ return LAST_VALUE_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "last_value";
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_last_value>(thd, this); }
+};
+
+class Item_sum_nth_value : public Item_sum_hybrid_simple
+{
+ public:
+ Item_sum_nth_value(THD *thd, Item *arg_expr, Item* offset_expr) :
+ Item_sum_hybrid_simple(thd, arg_expr, offset_expr) {}
+
+ enum Sumfunctype sum_func() const
+ {
+ return NTH_VALUE_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "nth_value";
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_nth_value>(thd, this); }
+};
+
+class Item_sum_lead : public Item_sum_hybrid_simple
+{
+ public:
+ Item_sum_lead(THD *thd, Item *arg_expr, Item* offset_expr) :
+ Item_sum_hybrid_simple(thd, arg_expr, offset_expr) {}
+
+ enum Sumfunctype sum_func() const
+ {
+ return LEAD_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "lead";
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_lead>(thd, this); }
+};
+
+class Item_sum_lag : public Item_sum_hybrid_simple
+{
+ public:
+ Item_sum_lag(THD *thd, Item *arg_expr, Item* offset_expr) :
+ Item_sum_hybrid_simple(thd, arg_expr, offset_expr) {}
+
+ enum Sumfunctype sum_func() const
+ {
+ return LAG_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "lag";
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_lag>(thd, this); }
+};
+
+
+class Partition_row_count
+{
+public:
+ Partition_row_count() :partition_row_count_(0) { }
+ void set_partition_row_count(ulonglong count)
+ {
+ partition_row_count_ = count;
+ }
+ double calc_val_real(bool *null_value,
+ ulonglong current_row_count)
+ {
+ if ((*null_value= (partition_row_count_ == 0)))
+ return 0;
+ return static_cast<double>(current_row_count) / partition_row_count_;
+ }
+protected:
+ longlong get_row_count() { return partition_row_count_; }
+ ulonglong partition_row_count_;
+};
+
+
+class Current_row_count
+{
+public:
+ Current_row_count() :current_row_count_(0) { }
+protected:
+ ulonglong get_row_number() { return current_row_count_ ; }
+ ulonglong current_row_count_;
+};
+
+
+/*
+ @detail
+ "The relative rank of a row R is defined as (RK-1)/(NR-1), where RK is
+ defined to be the RANK of R and NR is defined to be the number of rows in
+ the window partition of R."
+
+ Computation of this function requires two passes:
+ - First pass to find #rows in the partition
+ This is held within the row_count context.
+ - Second pass to compute rank of current row and the value of the function
+*/
+class Item_sum_percent_rank: public Item_sum_double,
+ public Partition_row_count
+{
+ public:
+ Item_sum_percent_rank(THD *thd)
+ : Item_sum_double(thd), cur_rank(1), peer_tracker(NULL) {}
+
+ longlong val_int()
+ {
+ /*
+ Percent rank is a real value so calling the integer value should never
+ happen. It makes no sense as it gets truncated to either 0 or 1.
+ */
+ DBUG_ASSERT(0);
+ return 0;
+ }
+
+ double val_real()
+ {
+ /*
+ We can not get the real value without knowing the number of rows
+ in the partition. Don't divide by 0.
+ */
+ ulonglong partition_rows = get_row_count();
+ null_value= partition_rows > 0 ? false : true;
+
+ return partition_rows > 1 ?
+ static_cast<double>(cur_rank - 1) / (partition_rows - 1) : 0;
+ }
+
+ enum Sumfunctype sum_func () const
+ {
+ return PERCENT_RANK_FUNC;
+ }
+
+ const char*func_name() const
+ {
+ return "percent_rank";
+ }
+
+ void update_field() {}
+
+ void clear()
+ {
+ cur_rank= 1;
+ row_number= 0;
+ }
+ bool add();
+ const Type_handler *type_handler() const { return &type_handler_double; }
+
+ bool fix_length_and_dec()
+ {
+ decimals = 10; // TODO-cvicentiu find out how many decimals the standard
+ // requires.
+ return FALSE;
+ }
+
+ void setup_window_func(THD *thd, Window_spec *window_spec);
+
+ void reset_field() { DBUG_ASSERT(0); }
+
+ void set_partition_row_count(ulonglong count)
+ {
+ Partition_row_count::set_partition_row_count(count);
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_percent_rank>(thd, this); }
+
+ private:
+ longlong cur_rank; // Current rank of the current row.
+ longlong row_number; // Value if this were ROW_NUMBER() function.
+
+ Group_bound_tracker *peer_tracker;
+
+ void cleanup()
+ {
+ if (peer_tracker)
+ {
+ delete peer_tracker;
+ peer_tracker= NULL;
+ }
+ Item_sum_num::cleanup();
+ }
+};
+
+
+
+
+/*
+ @detail
+ "The relative rank of a row R is defined as NP/NR, where
+ - NP is defined to be the number of rows preceding or peer with R in the
+ window ordering of the window partition of R
+ - NR is defined to be the number of rows in the window partition of R.
+
+ Just like with Item_sum_percent_rank, computation of this function requires
+ two passes.
+*/
+
+class Item_sum_cume_dist: public Item_sum_double,
+ public Partition_row_count,
+ public Current_row_count
+{
+ public:
+ Item_sum_cume_dist(THD *thd) :Item_sum_double(thd) { }
+ Item_sum_cume_dist(THD *thd, Item *arg) :Item_sum_double(thd, arg) { }
+
+ double val_real()
+ {
+ return calc_val_real(&null_value, current_row_count_);
+ }
+
+ bool add()
+ {
+ current_row_count_++;
+ return false;
+ }
+
+ enum Sumfunctype sum_func() const
+ {
+ return CUME_DIST_FUNC;
+ }
+
+ void clear()
+ {
+ current_row_count_= 0;
+ partition_row_count_= 0;
+ }
+
+ const char*func_name() const
+ {
+ return "cume_dist";
+ }
+
+ void update_field() {}
+ const Type_handler *type_handler() const { return &type_handler_double; }
+
+ bool fix_length_and_dec()
+ {
+ decimals = 10; // TODO-cvicentiu find out how many decimals the standard
+ // requires.
+ return FALSE;
+ }
+
+ void reset_field() { DBUG_ASSERT(0); }
+
+ void set_partition_row_count(ulonglong count)
+ {
+ Partition_row_count::set_partition_row_count(count);
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_cume_dist>(thd, this); }
+
+};
+
+class Item_sum_ntile : public Item_sum_int,
+ public Partition_row_count,
+ public Current_row_count
+{
+ public:
+ Item_sum_ntile(THD* thd, Item* num_quantiles_expr) :
+ Item_sum_int(thd, num_quantiles_expr), n_old_val_(0)
+ { }
+
+ longlong val_int()
+ {
+ if (get_row_count() == 0)
+ {
+ null_value= true;
+ return 0;
+ }
+
+ longlong num_quantiles= get_num_quantiles();
+
+ if (num_quantiles <= 0 ||
+ (static_cast<ulonglong>(num_quantiles) != n_old_val_ && n_old_val_ > 0))
+ {
+ my_error(ER_INVALID_NTILE_ARGUMENT, MYF(0));
+ return true;
+ }
+ n_old_val_= static_cast<ulonglong>(num_quantiles);
+ null_value= false;
+ ulonglong quantile_size = get_row_count() / num_quantiles;
+ ulonglong extra_rows = get_row_count() - quantile_size * num_quantiles;
+
+ if (current_row_count_ <= extra_rows * (quantile_size + 1))
+ return (current_row_count_ - 1) / (quantile_size + 1) + 1;
+
+ return (current_row_count_ - 1 - extra_rows) / quantile_size + 1;
+ }
+
+ bool add()
+ {
+ current_row_count_++;
+ return false;
+ }
+
+ enum Sumfunctype sum_func() const
+ {
+ return NTILE_FUNC;
+ }
+
+ void clear()
+ {
+ current_row_count_= 0;
+ partition_row_count_= 0;
+ n_old_val_= 0;
+ }
+
+ const char*func_name() const
+ {
+ return "ntile";
+ }
+
+ void update_field() {}
+
+ const Type_handler *type_handler() const { return &type_handler_slonglong; }
+
+ void reset_field() { DBUG_ASSERT(0); }
+
+ void set_partition_row_count(ulonglong count)
+ {
+ Partition_row_count::set_partition_row_count(count);
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_ntile>(thd, this); }
+
+ private:
+ longlong get_num_quantiles() { return args[0]->val_int(); }
+ ulonglong n_old_val_;
+};
+
+class Item_sum_percentile_disc : public Item_sum_num,
+ public Type_handler_hybrid_field_type,
+ public Partition_row_count,
+ public Current_row_count
+{
+public:
+ Item_sum_percentile_disc(THD *thd, Item* arg) : Item_sum_num(thd, arg),
+ Type_handler_hybrid_field_type(&type_handler_slonglong),
+ value(NULL), val_calculated(FALSE), first_call(TRUE),
+ prev_value(0), order_item(NULL){}
+
+ double val_real()
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return 0;
+ }
+ null_value= false;
+ return value->val_real();
+ }
+
+ longlong val_int()
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return 0;
+ }
+ null_value= false;
+ return value->val_int();
+ }
+
+ my_decimal* val_decimal(my_decimal* dec)
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return 0;
+ }
+ null_value= false;
+ return value->val_decimal(dec);
+ }
+
+ String* val_str(String *str)
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return 0;
+ }
+ null_value= false;
+ return value->val_str(str);
+ }
+
+ bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return true;
+ }
+ null_value= false;
+ return value->get_date(thd, ltime, fuzzydate);
+ }
+
+ bool val_native(THD *thd, Native *to)
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return true;
+ }
+ null_value= false;
+ return value->val_native(thd, to);
+ }
+
+ bool add()
+ {
+ Item *arg= get_arg(0);
+ if (arg->is_null())
+ return false;
+
+ if (first_call)
+ {
+ prev_value= arg->val_real();
+ if (prev_value > 1 || prev_value < 0)
+ {
+ my_error(ER_ARGUMENT_OUT_OF_RANGE, MYF(0), func_name());
+ return true;
+ }
+ first_call= false;
+ }
+
+ double arg_val= arg->val_real();
+
+ if (prev_value != arg_val)
+ {
+ my_error(ER_ARGUMENT_NOT_CONSTANT, MYF(0), func_name());
+ return true;
+ }
+
+ if (val_calculated)
+ return false;
+
+ value->store(order_item);
+ value->cache_value();
+ if (value->null_value)
+ return false;
+
+ current_row_count_++;
+ double val= calc_val_real(&null_value, current_row_count_);
+
+ if (val >= prev_value && !val_calculated)
+ val_calculated= true;
+ return false;
+ }
+
+ enum Sumfunctype sum_func() const
+ {
+ return PERCENTILE_DISC_FUNC;
+ }
+
+ void clear()
+ {
+ val_calculated= false;
+ first_call= true;
+ value->clear();
+ partition_row_count_= 0;
+ current_row_count_= 0;
+ }
+
+ const char*func_name() const
+ {
+ return "percentile_disc";
+ }
+
+ void update_field() {}
+ const Type_handler *type_handler() const
+ {return Type_handler_hybrid_field_type::type_handler();}
+
+ bool fix_length_and_dec()
+ {
+ decimals = 10; // TODO-cvicentiu find out how many decimals the standard
+ // requires.
+ return FALSE;
+ }
+
+ void reset_field() { DBUG_ASSERT(0); }
+
+ void set_partition_row_count(ulonglong count)
+ {
+ Partition_row_count::set_partition_row_count(count);
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_percentile_disc>(thd, this); }
+ void setup_window_func(THD *thd, Window_spec *window_spec);
+ void setup_hybrid(THD *thd, Item *item);
+ bool fix_fields(THD *thd, Item **ref);
+
+private:
+ Item_cache *value;
+ bool val_calculated;
+ bool first_call;
+ double prev_value;
+ Item *order_item;
+};
+
+class Item_sum_percentile_cont : public Item_sum_double,
+ public Partition_row_count,
+ public Current_row_count
+{
+public:
+ Item_sum_percentile_cont(THD *thd, Item* arg) : Item_sum_double(thd, arg),
+ floor_value(NULL), ceil_value(NULL), first_call(TRUE),prev_value(0),
+ ceil_val_calculated(FALSE), floor_val_calculated(FALSE), order_item(NULL){}
+
+ double val_real()
+ {
+ if (get_row_count() == 0 || get_arg(0)->is_null())
+ {
+ null_value= true;
+ return 0;
+ }
+ null_value= false;
+ double val= 1 + prev_value * (get_row_count()-1);
+
+ /*
+ Applying the formula to get the value
+ If (CRN = FRN = RN) then the result is (value of expression from row at RN)
+ Otherwise the result is
+ (CRN - RN) * (value of expression for row at FRN) +
+ (RN - FRN) * (value of expression for row at CRN)
+ */
+
+ if(ceil(val) == floor(val))
+ return floor_value->val_real();
+
+ double ret_val= ((val - floor(val)) * ceil_value->val_real()) +
+ ((ceil(val) - val) * floor_value->val_real());
+
+ return ret_val;
+ }
+
+ bool add()
+ {
+ Item *arg= get_arg(0);
+ if (arg->is_null())
+ return false;
+
+ if (first_call)
+ {
+ first_call= false;
+ prev_value= arg->val_real();
+ if (prev_value > 1 || prev_value < 0)
+ {
+ my_error(ER_ARGUMENT_OUT_OF_RANGE, MYF(0), func_name());
+ return true;
+ }
+ }
+
+ double arg_val= arg->val_real();
+ if (prev_value != arg_val)
+ {
+ my_error(ER_ARGUMENT_NOT_CONSTANT, MYF(0), func_name());
+ return true;
+ }
+
+ if (!floor_val_calculated)
+ {
+ floor_value->store(order_item);
+ floor_value->cache_value();
+ if (floor_value->null_value)
+ return false;
+ }
+ if (floor_val_calculated && !ceil_val_calculated)
+ {
+ ceil_value->store(order_item);
+ ceil_value->cache_value();
+ if (ceil_value->null_value)
+ return false;
+ }
+
+ current_row_count_++;
+ double val= 1 + prev_value * (get_row_count()-1);
+
+ if (!floor_val_calculated && get_row_number() == floor(val))
+ floor_val_calculated= true;
+
+ if (!ceil_val_calculated && get_row_number() == ceil(val))
+ ceil_val_calculated= true;
+ return false;
+ }
+
+ enum Sumfunctype sum_func() const
+ {
+ return PERCENTILE_CONT_FUNC;
+ }
+
+ void clear()
+ {
+ first_call= true;
+ floor_value->clear();
+ ceil_value->clear();
+ floor_val_calculated= false;
+ ceil_val_calculated= false;
+ partition_row_count_= 0;
+ current_row_count_= 0;
+ }
+
+ const char*func_name() const
+ {
+ return "percentile_cont";
+ }
+ void update_field() {}
+
+ bool fix_length_and_dec()
+ {
+ decimals = 10; // TODO-cvicentiu find out how many decimals the standard
+ // requires.
+ return FALSE;
+ }
+
+ void reset_field() { DBUG_ASSERT(0); }
+
+ void set_partition_row_count(ulonglong count)
+ {
+ Partition_row_count::set_partition_row_count(count);
+ }
+
+ Item *get_copy(THD *thd)
+ { return get_item_copy<Item_sum_percentile_cont>(thd, this); }
+ void setup_window_func(THD *thd, Window_spec *window_spec);
+ void setup_hybrid(THD *thd, Item *item);
+ bool fix_fields(THD *thd, Item **ref);
+
+private:
+ Item_cache *floor_value;
+ Item_cache *ceil_value;
+ bool first_call;
+ double prev_value;
+ bool ceil_val_calculated;
+ bool floor_val_calculated;
+ Item *order_item;
+};
+
+
+
+
+class Item_window_func : public Item_func_or_sum
+{
+ /* Window function parameters as we've got them from the parser */
+public:
+ LEX_CSTRING *window_name;
+public:
+ Window_spec *window_spec;
+
+public:
+ Item_window_func(THD *thd, Item_sum *win_func, LEX_CSTRING *win_name)
+ : Item_func_or_sum(thd, (Item *) win_func),
+ window_name(win_name), window_spec(NULL),
+ force_return_blank(true),
+ read_value_from_result_field(false) {}
+
+ Item_window_func(THD *thd, Item_sum *win_func, Window_spec *win_spec)
+ : Item_func_or_sum(thd, (Item *) win_func),
+ window_name(NULL), window_spec(win_spec),
+ force_return_blank(true),
+ read_value_from_result_field(false) {}
+
+ Item_sum *window_func() const { return (Item_sum *) args[0]; }
+
+ void update_used_tables();
+
+ /*
+ This is used by filesort to mark the columns it needs to read (because they
+ participate in the sort criteria and/or row retrieval. Window functions can
+ only be used in sort criteria).
+
+ Sorting by window function value is only done after the window functions
+ have been computed. In that case, window function will need to read its
+ temp.table field. In order to allow that, mark that field in the read_set.
+ */
+ bool register_field_in_read_map(void *arg)
+ {
+ TABLE *table= (TABLE*) arg;
+ if (result_field && (result_field->table == table || !table))
+ {
+ bitmap_set_bit(result_field->table->read_set, result_field->field_index);
+ }
+ return 0;
+ }
+
+ bool is_frame_prohibited() const
+ {
+ switch (window_func()->sum_func()) {
+ case Item_sum::ROW_NUMBER_FUNC:
+ case Item_sum::RANK_FUNC:
+ case Item_sum::DENSE_RANK_FUNC:
+ case Item_sum::PERCENT_RANK_FUNC:
+ case Item_sum::CUME_DIST_FUNC:
+ case Item_sum::NTILE_FUNC:
+ case Item_sum::PERCENTILE_CONT_FUNC:
+ case Item_sum::PERCENTILE_DISC_FUNC:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ bool requires_special_cursors() const
+ {
+ switch (window_func()->sum_func()) {
+ case Item_sum::FIRST_VALUE_FUNC:
+ case Item_sum::LAST_VALUE_FUNC:
+ case Item_sum::NTH_VALUE_FUNC:
+ case Item_sum::LAG_FUNC:
+ case Item_sum::LEAD_FUNC:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ bool requires_partition_size() const
+ {
+ switch (window_func()->sum_func()) {
+ case Item_sum::PERCENT_RANK_FUNC:
+ case Item_sum::CUME_DIST_FUNC:
+ case Item_sum::NTILE_FUNC:
+ case Item_sum::PERCENTILE_CONT_FUNC:
+ case Item_sum::PERCENTILE_DISC_FUNC:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ bool requires_peer_size() const
+ {
+ switch (window_func()->sum_func()) {
+ case Item_sum::CUME_DIST_FUNC:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ bool is_order_list_mandatory() const
+ {
+ switch (window_func()->sum_func()) {
+ case Item_sum::RANK_FUNC:
+ case Item_sum::DENSE_RANK_FUNC:
+ case Item_sum::PERCENT_RANK_FUNC:
+ case Item_sum::CUME_DIST_FUNC:
+ case Item_sum::LAG_FUNC:
+ case Item_sum::LEAD_FUNC:
+ case Item_sum::PERCENTILE_CONT_FUNC:
+ case Item_sum::PERCENTILE_DISC_FUNC:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ bool only_single_element_order_list() const
+ {
+ switch (window_func()->sum_func()){
+ case Item_sum::PERCENTILE_CONT_FUNC:
+ case Item_sum::PERCENTILE_DISC_FUNC:
+ return true;
+ default:
+ return false;
+ }
+ }
+
+ bool check_result_type_of_order_item();
+
+
+
+ /*
+ Computation functions.
+ TODO: consoder merging these with class Group_bound_tracker.
+ */
+ void setup_partition_border_check(THD *thd);
+
+ const Type_handler *type_handler() const
+ {
+ return ((Item_sum *) args[0])->type_handler();
+ }
+ enum Item::Type type() const { return Item::WINDOW_FUNC_ITEM; }
+
+private:
+ /*
+ Window functions are very special functions, so val_() methods have
+ special meaning for them:
+
+ - Phase#1, "Initial" we run the join and put its result into temporary
+ table. For window functions, we write the default value (NULL?) as
+ a placeholder.
+
+ - Phase#2: "Computation": executor does the scan in {PARTITION, ORDER BY}
+ order of this window function. It calls appropriate methods to inform
+ the window function about rows entering/leaving the window.
+ It calls window_func()->val_int() so that current window function value
+ can be saved and stored in the temp.table.
+
+ - Phase#3: "Retrieval" the temporary table is read and passed to query
+ output. However, Item_window_func still remains in the select list,
+ so item_windowfunc->val_int() will be called.
+ During Phase#3, read_value_from_result_field= true.
+ */
+ bool force_return_blank;
+ bool read_value_from_result_field;
+ void print_for_percentile_functions(String *str, enum_query_type query_type);
+
+public:
+ void set_phase_to_initial()
+ {
+ force_return_blank= true;
+ read_value_from_result_field= false;
+ }
+ void set_phase_to_computation()
+ {
+ force_return_blank= false;
+ read_value_from_result_field= false;
+ }
+ void set_phase_to_retrieval()
+ {
+ force_return_blank= false;
+ read_value_from_result_field= true;
+ }
+
+ bool is_null()
+ {
+ if (force_return_blank)
+ return true;
+
+ if (read_value_from_result_field)
+ return result_field->is_null();
+
+ return window_func()->is_null();
+ }
+
+ double val_real()
+ {
+ double res;
+ if (force_return_blank)
+ {
+ res= 0.0;
+ null_value= true;
+ }
+ else if (read_value_from_result_field)
+ {
+ res= result_field->val_real();
+ null_value= result_field->is_null();
+ }
+ else
+ {
+ res= window_func()->val_real();
+ null_value= window_func()->null_value;
+ }
+ return res;
+ }
+
+ longlong val_int()
+ {
+ longlong res;
+ if (force_return_blank)
+ {
+ res= 0;
+ null_value= true;
+ }
+ else if (read_value_from_result_field)
+ {
+ res= result_field->val_int();
+ null_value= result_field->is_null();
+ }
+ else
+ {
+ res= window_func()->val_int();
+ null_value= window_func()->null_value;
+ }
+ return res;
+ }
+
+ String* val_str(String* str)
+ {
+ String *res;
+ if (force_return_blank)
+ {
+ null_value= true;
+ res= NULL;
+ }
+ else if (read_value_from_result_field)
+ {
+ if ((null_value= result_field->is_null()))
+ res= NULL;
+ else
+ res= result_field->val_str(str);
+ }
+ else
+ {
+ res= window_func()->val_str(str);
+ null_value= window_func()->null_value;
+ }
+ return res;
+ }
+
+ bool val_native(THD *thd, Native *to)
+ {
+ if (force_return_blank)
+ return null_value= true;
+ if (read_value_from_result_field)
+ return val_native_from_field(result_field, to);
+ return val_native_from_item(thd, window_func(), to);
+ }
+
+ my_decimal* val_decimal(my_decimal* dec)
+ {
+ my_decimal *res;
+ if (force_return_blank)
+ {
+ null_value= true;
+ res= NULL;
+ }
+ else if (read_value_from_result_field)
+ {
+ if ((null_value= result_field->is_null()))
+ res= NULL;
+ else
+ res= result_field->val_decimal(dec);
+ }
+ else
+ {
+ res= window_func()->val_decimal(dec);
+ null_value= window_func()->null_value;
+ }
+ return res;
+ }
+
+ bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
+ {
+ bool res;
+ if (force_return_blank)
+ {
+ null_value= true;
+ res= true;
+ }
+ else if (read_value_from_result_field)
+ {
+ if ((null_value= result_field->is_null()))
+ res= true;
+ else
+ res= result_field->get_date(ltime, fuzzydate);
+ }
+ else
+ {
+ res= window_func()->get_date(thd, ltime, fuzzydate);
+ null_value= window_func()->null_value;
+ }
+ return res;
+ }
+
+ void split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array,
+ List<Item> &fields, uint flags);
+
+ bool fix_length_and_dec()
+ {
+ Type_std_attributes::set(window_func());
+ return FALSE;
+ }
+
+ const char* func_name() const { return "WF"; }
+
+ bool fix_fields(THD *thd, Item **ref);
+
+ bool resolve_window_name(THD *thd);
+
+ void print(String *str, enum_query_type query_type);
+
+ Item *get_copy(THD *thd) { return 0; }
+
+};
+
+#endif /* ITEM_WINDOWFUNC_INCLUDED */