Fixed bug in HAVING when refering to RAND() through alias

(BUG 8216)


mysql-test/r/group_by.result:
  New test case
mysql-test/r/user_var.result:
  Test changed (to be more correct) with bug fix
mysql-test/t/group_by.test:
  Added test for HAVING bug
sql/item_cmpfunc.cc:
  Fixed bug in HAVING when refering to RAND()
sql/item_func.cc:
  Fixed bug in HAVING when refering to RAND()
sql/item_row.cc:
  Fixed bug in HAVING when refering to RAND()
sql/item_strfunc.cc:
  Fixed bug in HAVING when refering to RAND()
sql/unireg.h:
  Added PSEUDO_TABLES_BITS for easy testing of real table reference

mysql-test/r/group_by.result

@@ -629,15 +629,6 @@ explain SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	6	Using filesort
 DROP TABLE t1;
-create table t1 ( col1 int, col2 int );
-insert into t1 values (1,1),(1,2),(1,3),(2,1),(2,2);
-select group_concat( distinct col1 ) as alias from t1
-group by col2 having alias like '%';
-alias
-1,2
-1,2
-1
-drop table t1;
 create table t1 (a int);
 insert into t1 values(null);
 select min(a) is null from t1;
@@ -650,3 +641,39 @@ select 1 and min(a) is null from t1;
 1 and min(a) is null
 1
 drop table t1;
+create table t1 ( col1 int, col2 int );
+insert into t1 values (1,1),(1,2),(1,3),(2,1),(2,2);
+select group_concat( distinct col1 ) as alias from t1
+group by col2 having alias like '%';
+alias
+1,2
+1,2
+1
+drop table t1;
+create table t1 (a integer, b integer, c integer);
+insert into t1 (a,b) values (1,2),(1,3),(2,5);
+select a, 0.1*0+1 r2, sum(1) r1 from t1 where a = 1 group  by a having r1>1 and r2=1;
+a	r2	r1
+1	1.0	2
+select a, rand()*0+1 r2, sum(1) r1 from t1 where a = 1 group  by a having r1>1 and r2=1;
+a	r2	r1
+1	1	2
+select a,sum(b) from t1 where a=1 group by c;
+a	sum(b)
+1	5
+select a*sum(b) from t1 where a=1 group by c;
+a*sum(b)
+5
+select sum(a)*sum(b) from t1 where a=1 group by c;
+sum(a)*sum(b)
+10
+select a,sum(b) from t1 where a=1 group by c having a=1;
+a	sum(b)
+1	5
+select a as d,sum(b) from t1 where a=1 group by c having d=1;
+d	sum(b)
+1	5
+select sum(a)*sum(b) as d from t1 where a=1 group by c having d > 0;
+d
+10
+drop table t1;

mysql-test/r/user_var.result

@@ -109,8 +109,8 @@ select @a:=0;
 select @a, @a:=@a+count(*), count(*), @a from t1 group by i;
 @a	@a:=@a+count(*)	count(*)	@a
 0	1	1	0
-0	2	2	0
-0	3	3	0
+0	3	2	0
+0	6	3	0
 select @a:=0;
 @a:=0
 0

mysql-test/t/group_by.test

@@ -457,6 +457,14 @@ SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL;
 explain SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL;
 DROP TABLE t1;
 
+#Test for BUG#6976: Aggregate functions have incorrect NULL-ness
+create table t1 (a int);
+insert into t1 values(null);
+select min(a) is null from t1;
+select min(a) is null or null from t1;
+select 1 and min(a) is null from t1;
+drop table t1;
+
 # Test for BUG#5400: GROUP_CONCAT returns everything twice.
 create table t1 ( col1 int, col2 int );
 insert into t1 values (1,1),(1,2),(1,3),(2,1),(2,2);
@@ -465,12 +473,18 @@ select group_concat( distinct col1 ) as alias from t1
 
 drop table t1;
 
+#
+# Test BUG#8216 when referring in HAVING to n alias which is rand() function
+#
 
-#Test for BUG#6976: Aggregate functions have incorrect NULL-ness
-create table t1 (a int);
-insert into t1 values(null);
-select min(a) is null from t1;
-select min(a) is null or null from t1;
-select 1 and min(a) is null from t1;
+create table t1 (a integer, b integer, c integer);
+insert into t1 (a,b) values (1,2),(1,3),(2,5);
+select a, 0.1*0+1 r2, sum(1) r1 from t1 where a = 1 group  by a having r1>1 and r2=1;
+select a, rand()*0+1 r2, sum(1) r1 from t1 where a = 1 group  by a having r1>1 and r2=1;
+select a,sum(b) from t1 where a=1 group by c;
+select a*sum(b) from t1 where a=1 group by c;
+select sum(a)*sum(b) from t1 where a=1 group by c;
+select a,sum(b) from t1 where a=1 group by c having a=1;
+select a as d,sum(b) from t1 where a=1 group by c having d=1;
+select sum(a)*sum(b) as d from t1 where a=1 group by c having d > 0;
 drop table t1;
-

sql/item_cmpfunc.cc

@@ -1960,6 +1960,36 @@ bool Item_cond::walk(Item_processor processor, byte *arg)
   return Item_func::walk(processor, arg);
 }
 
+
+/*
+  Move SUM items out from item tree and replace with reference
+
+  SYNOPSIS
+  split_sum_func()
+  thd			Thread handler
+  ref_pointer_array	Pointer to array of reference fields
+  fields		All fields in select
+
+  NOTES
+   This function is run on all expression (SELECT list, WHERE, HAVING etc)
+   that have or refer (HAVING) to a SUM expression.
+
+   The split is done to get an unique item for each SUM function
+   so that we can easily find and calculate them.
+   (Calculation done by update_sum_func() and copy_sum_funcs() in
+   sql_select.cc)
+
+   All found SUM items are added FIRST in the fields list and
+   we replace the item with a reference.
+
+   We also replace all functions without side effects (like RAND() or UDF's)
+   that uses columns as arguments.
+   For functions with side effects, we just remember any fields referred
+   by the function to ensure that we get a copy of the field value for the
+   first accepted row. This ensures that we can do things like
+   SELECT a*SUM(b) FROM t1 WHERE a=1
+*/
+
 void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
                                List<Item> &fields)
 {
@@ -1969,10 +1999,22 @@ void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
   const_item_cache=0;
   while ((item=li++))
   {
-    if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
+    /* with_sum_func is set for items that contains a SUM expression */
+    if (item->type() != SUM_FUNC_ITEM &&
+        (item->with_sum_func ||
+         (item->used_tables() & PSEUDO_TABLE_BITS)))
       item->split_sum_func(thd, ref_pointer_array, fields);
-    else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
+    else if (item->type() == SUM_FUNC_ITEM ||
+             (item->used_tables() && item->type() != REF_ITEM))
     {
+      /*
+        Replace item with a reference so that we can easily calculate
+        it (in case of sum functions) or copy it (in case of fields)
+
+        The test above is to ensure we don't do a reference for things
+        that are constants or are not yet calculated as in:
+        SELECT RAND() as r1, SUM(a) as r2 FROM t1 HAVING r1 > 1 AND r2 > 0
+      */
       Item **ref= li.ref();
       uint el= fields.elements;
       ref_pointer_array[el]= item;

sql/item_func.cc

@@ -351,6 +351,7 @@ bool Item_func::walk (Item_processor processor, byte *argument)
   return (this->*processor)(argument);
 }
 
+
 void Item_func::split_sum_func(THD *thd, Item **ref_pointer_array,
                                List<Item> &fields)
 {
@@ -358,9 +359,12 @@ void Item_func::split_sum_func(THD *thd, Item **ref_pointer_array,
   for (arg= args, arg_end= args+arg_count; arg != arg_end ; arg++)
   {
     Item *item=* arg;
-    if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
+    if (item->type() != SUM_FUNC_ITEM &&
+        (item->with_sum_func ||
+         (item->used_tables() & PSEUDO_TABLE_BITS)))
       item->split_sum_func(thd, ref_pointer_array, fields);
-    else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
+    else if (item->type() == SUM_FUNC_ITEM ||
+             (item->used_tables() && item->type() != REF_ITEM))
     {
       uint el= fields.elements;
       ref_pointer_array[el]= item;

sql/item_row.cc

@@ -84,15 +84,20 @@ bool Item_row::fix_fields(THD *thd, TABLE_LIST *tabl, Item **ref)
   return 0;
 }
 
+
 void Item_row::split_sum_func(THD *thd, Item **ref_pointer_array,
                               List<Item> &fields)
 {
   Item **arg, **arg_end;
   for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
   {
-    if ((*arg)->with_sum_func && (*arg)->type() != SUM_FUNC_ITEM)
-      (*arg)->split_sum_func(thd, ref_pointer_array, fields);
-    else if ((*arg)->used_tables() || (*arg)->type() == SUM_FUNC_ITEM)
+    Item *item= *arg;
+    if (item->type() != SUM_FUNC_ITEM &&
+        (item->with_sum_func ||
+         (item->used_tables() & PSEUDO_TABLE_BITS)))
+      item->split_sum_func(thd, ref_pointer_array, fields);
+    else if (item->type() == SUM_FUNC_ITEM ||
+             (item->used_tables() && item->type() != REF_ITEM))
     {
       uint el= fields.elements;
       ref_pointer_array[el]=*arg;

sql/item_strfunc.cc

@@ -1758,9 +1758,12 @@ String *Item_func_elt::val_str(String *str)
 void Item_func_make_set::split_sum_func(THD *thd, Item **ref_pointer_array,
 					List<Item> &fields)
 {
-  if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
+  if (item->type() != SUM_FUNC_ITEM &&
+      (item->with_sum_func ||
+       (item->used_tables() & PSEUDO_TABLE_BITS)))
     item->split_sum_func(thd, ref_pointer_array, fields);
-  else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
+  else if (item->type() == SUM_FUNC_ITEM ||
+           (item->used_tables() && item->type() != REF_ITEM))
   {
     uint el= fields.elements;
     ref_pointer_array[el]=item;

sql/unireg.h

@@ -72,6 +72,8 @@
 #define PARAM_TABLE_BIT	(((table_map) 1) << (sizeof(table_map)*8-3))
 #define OUTER_REF_TABLE_BIT	(((table_map) 1) << (sizeof(table_map)*8-2))
 #define RAND_TABLE_BIT	(((table_map) 1) << (sizeof(table_map)*8-1))
+#define PSEUDO_TABLE_BITS (PARAM_TABLE_BIT | OUTER_REF_TABLE_BIT | \
+                           RAND_TABLE_BIT)
 #define MAX_FIELDS	4096			/* Limit in the .frm file */
 
 #define MAX_SORT_MEMORY (2048*1024-MALLOC_OVERHEAD)