MDEV-10017: Get unexpected `Empty Set` for correlated subquery with aggregate functions (part 1)

Make aggregate function dependency visible.

mysql-test/r/func_group.result

@@ -2379,5 +2379,23 @@ companynr	AVG(fld1)	avg1	avg2
 37	9223372036854775805.0000	9223372036854775805	9223372036854775805
 DROP TABLE t1;
 #
+# case where aggregate resolved in the local SELECT
+# but outer ones are checked
+#
+create table t10 (a int , b int, c int);
+insert into t10 values (0,0,0),(1,1,1);
+create table t11 as select * from t10;
+create table t12 as select * from t10;
+explain extended select a from t10 where c<3 or a in (select c from t12 union select max(t10.b) from t11 group by t11.c);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	t10	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+2	DEPENDENT SUBQUERY	t12	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+3	DEPENDENT UNION	t11	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
+Warnings:
+Note	1276	Field or reference 'test.t10.b' of SELECT #3 was resolved in SELECT #1
+Note	1003	select `test`.`t10`.`a` AS `a` from `test`.`t10` where ((`test`.`t10`.`c` < 3) or <expr_cache><`test`.`t10`.`a`,`test`.`t10`.`b`>(<in_optimizer>(`test`.`t10`.`a`,<exists>(select `test`.`t12`.`c` from `test`.`t12` where (<cache>(`test`.`t10`.`a`) = `test`.`t12`.`c`) union select max(`test`.`t10`.`b`) from `test`.`t11` group by `test`.`t11`.`c` having (<cache>(`test`.`t10`.`a`) = <ref_null_helper>(max(`test`.`t10`.`b`)))))))
+drop table t10,t11,t12;
+#
 # End of 10.1 tests
 #

mysql-test/r/subselect3.result

@@ -890,6 +890,7 @@ ERROR 42S22: Unknown column 'c' in 'field list'
 SHOW WARNINGS;
 Level	Code	Message
 Note	1276	Field or reference 'test.t1.a' of SELECT #3 was resolved in SELECT #2
+Note	1981	Aggregate function 'count()' of SELECT #3 belongs to SELECT #2
 Note	1276	Field or reference 'test.t1.c' of SELECT #3 was resolved in SELECT #2
 Error	1054	Unknown column 'c' in 'field list'
 DROP TABLE t1;

mysql-test/r/subselect3_jcl6.result

@@ -900,6 +900,7 @@ ERROR 42S22: Unknown column 'c' in 'field list'
 SHOW WARNINGS;
 Level	Code	Message
 Note	1276	Field or reference 'test.t1.a' of SELECT #3 was resolved in SELECT #2
+Note	1981	Aggregate function 'count()' of SELECT #3 belongs to SELECT #2
 Note	1276	Field or reference 'test.t1.c' of SELECT #3 was resolved in SELECT #2
 Error	1054	Unknown column 'c' in 'field list'
 DROP TABLE t1;

mysql-test/r/subselect_mat.result

@@ -1139,6 +1139,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
+Note	1981	Aggregate function 'max()' of SELECT #3 belongs to SELECT #1
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` having <expr_cache><`test`.`t1`.`a`,`test`.`t1`.`b`,max(`test`.`t1`.`b`),max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`c` from `test`.`t2` where (<nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`,max(`test`.`t1`.`b`),max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where (max(`test`.`t1`.`b`) = `test`.`t3`.`e`) having (<cache>(`test`.`t2`.`d`) >= <ref_null_helper>(`test`.`t3`.`e`)))))) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`c`)))))
 select a from t1 group by a
 having a in (select c from t2 where d >= some(select e from t3 where max(b)=e));

mysql-test/r/subselect_sj_mat.result

@@ -1173,6 +1173,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
+Note	1981	Aggregate function 'max()' of SELECT #3 belongs to SELECT #1
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` having <expr_cache><`test`.`t1`.`a`,`test`.`t1`.`b`,max(`test`.`t1`.`b`),max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`c` from `test`.`t2` where (<nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`,max(`test`.`t1`.`b`),max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where (max(`test`.`t1`.`b`) = `test`.`t3`.`e`) having (<cache>(`test`.`t2`.`d`) >= <ref_null_helper>(`test`.`t3`.`e`)))))) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`c`)))))
 select a from t1 group by a
 having a in (select c from t2 where d >= some(select e from t3 where max(b)=e));

mysql-test/t/func_group.test

@@ -1647,6 +1647,16 @@ INSERT INTO t1 VALUES (3,0x7FFFFFFFFFFFFFFC,37);
 SELECT companynr, AVG(fld1), AVG(fld1)<<0 AS avg1, CAST(AVG(fld1) AS UNSIGNED)<<0 AS avg2 FROM t1 GROUP BY companynr;
 DROP TABLE t1;
 
+--echo #
+--echo # case where aggregate resolved in the local SELECT
+--echo # but outer ones are checked
+--echo #
+create table t10 (a int , b int, c int);
+insert into t10 values (0,0,0),(1,1,1);
+create table t11 as select * from t10;
+create table t12 as select * from t10;
+explain extended select a from t10 where c<3 or a in (select c from t12 union select max(t10.b) from t11 group by t11.c);
+drop table t10,t11,t12;
 --echo #
 --echo # End of 10.1 tests
 --echo #

sql/item_sum.cc

@@ -380,6 +380,16 @@ bool Item_sum::register_sum_func(THD *thd, Item **ref)
       sl->master_unit()->item->with_sum_func= 1;
   }
   thd->lex->current_select->mark_as_dependent(thd, aggr_sel, NULL);
+
+  if ((thd->lex->describe & DESCRIBE_EXTENDED) && aggr_sel)
+  {
+    push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+                        ER_WARN_AGGFUNC_DEPENDENCE,
+                        ER_THD(thd, ER_WARN_AGGFUNC_DEPENDENCE),
+                        func_name(),
+                        thd->lex->current_select->select_number,
+                        aggr_sel->select_number);
+  }
   return FALSE;
 }
 

sql/share/errmsg-utf8.txt

@@ -7139,3 +7139,6 @@ ER_KILL_QUERY_DENIED_ERROR
 ER_NO_EIS_FOR_FIELD
         eng "Engine-independent statistics are not collected for column '%s'"
         ukr "Незалежна від типу таблиці статистика не збирається для стовбця '%s'"
+ER_WARN_AGGFUNC_DEPENDENCE
+        eng "Aggregate function '%-.192s)' of SELECT #%d belongs to SELECT #%d"
+        ukr "Агрегатна функція '%-.192s)' з SELECTу #%d належить до SELECTу #%d"