Bug#27321: Wrong subquery result in a grouping select.

The Item_outer_ref class based on the Item_direct_ref class was always used
to represent an outer field. But if the outer select is a grouping one and the 
outer field isn't under an aggregate function which is aggregated in that
outer select an Item_ref object should be used to represent such a field.
If the outer select in which the outer field is resolved isn't grouping then
the Item_field class should be used to represent such a field.
This logic also should be used for an outer field resolved through its alias
name.

Now the Item_field::fix_outer_field() uses Item_outer_field objects to
represent aliased and non-aliased outer fields for grouping outer selects
only.
Now the fix_inner_refs() function chooses which class to use to access outer
field - the Item_ref or the Item_direct_ref. An object of the chosen class
substitutes the original field in the Item_outer_ref object.
The direct_ref and the found_in_select_list fields were added to the
Item_outer_ref class.


mysql-test/t/subselect3.test:
  Some test cases were corrected after the fix for the bug#27321.
mysql-test/r/subselect3.result:
  Some test cases were corrected after the fix for the bug#27321.
mysql-test/t/subselect.test:
  Added a test case for the bug#27321: Wrong subquery result in a grouping select.
mysql-test/r/subselect.result:
  Added a test case for the bug#27321: Wrong subquery result in a grouping select.
  Some test cases were corrected after this fix.
sql/sql_union.cc:
  Bug#27321: Wrong subquery result in a grouping select.
  Cleanup of the inner_refs_list.
sql/sql_select.cc:
  Bug#27321: Wrong subquery result in a grouping select.
  Now the fix_inner_refs() function chooses which class to use to access outer
  field - the Item_ref or the Item_direct_ref. An object of the chosen class
  substitutes the original field in the Item_outer_ref object.
  A comment is corrected.
sql/item.cc:
  Bug#27321: Wrong subquery result in a grouping select.
  Now the Item_field::fix_outer_field() uses Item_outer_field objects to
  represent aliased and non-aliased outer fields for grouping outer selects
  only.
sql/item.h:
  Bug#27321: Wrong subquery result in a grouping select.
  The direct_ref and the found_in_select_list fields were added to the
  Item_outer_ref class.

1 files changed, 68 insertions, 3 deletions

diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result
index 81f087fe8fa..8357b209ae6 100644
--- a/mysql-test/r/subselect.result
+++ b/mysql-test/r/subselect.result
@@ -48,7 +48,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1276	Field or reference 'a' of SELECT #3 was resolved in SELECT #1
+Note	1276	Field or reference 'b.a' of SELECT #3 was resolved in SELECT #1
 Note	1276	Field or reference 'b.a' of SELECT #3 was resolved in SELECT #1
 Note	1003	select 1 AS `1` from (select 1 AS `a`) `b` having ((select '1' AS `a`) = 1)
 SELECT 1 FROM (SELECT 1 as a) as b HAVING (SELECT a)=1;
@@ -330,7 +330,7 @@ patient_uq	clinic_uq
 explain extended select * from t6 where exists (select * from t7 where uq = clinic_uq);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t6	ALL	NULL	NULL	NULL	NULL	4	Using where
-2	DEPENDENT SUBQUERY	t7	eq_ref	PRIMARY	PRIMARY	4	t6.clinic_uq	1	Using where; Using index
+2	DEPENDENT SUBQUERY	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.clinic_uq	1	Using index
 Warnings:
 Note	1276	Field or reference 'test.t6.clinic_uq' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t6`.`patient_uq` AS `patient_uq`,`test`.`t6`.`clinic_uq` AS `clinic_uq` from `test`.`t6` where exists(select 1 AS `Not_used` from `test`.`t7` where (`test`.`t7`.`uq` = `test`.`t6`.`clinic_uq`))
@@ -1741,7 +1741,7 @@ Note	1003	select `test`.`t1`.`id` AS `id`,`test`.`t1`.`text` AS `text` from `tes
 explain extended select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	tt	ALL	NULL	NULL	NULL	NULL	12	Using where
-2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	tt.id	1	Using where; Using index
+2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	test.tt.id	1	Using where; Using index
 Warnings:
 Note	1276	Field or reference 'test.tt.id' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`tt`.`id` AS `id`,`test`.`tt`.`text` AS `text` from `test`.`t1` `tt` where (not(exists(select `test`.`t1`.`id` AS `id` from `test`.`t1` where ((`test`.`t1`.`id` < 8) and (`test`.`t1`.`id` = `test`.`tt`.`id`)) having (`test`.`t1`.`id` is not null))))
@@ -3924,3 +3924,68 @@ c	a	(SELECT GROUP_CONCAT(COUNT(a)+1) FROM t2 WHERE m = a)
 3	3	4
 1	4	2,2
 DROP table t1,t2;
+CREATE TABLE t1 (a int, b INT, d INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b));
+INSERT INTO t1 VALUES (1,1,0,'a'), (1,2,0,'b'), (1,3,0,'c'), (1,4,0,'d'),
+(1,5,0,'e'), (2,1,0,'f'), (2,2,0,'g'), (2,3,0,'h'), (3,4,0,'i'), (3,3,0,'j'),
+(3,2,0,'k'), (3,1,0,'l'), (1,9,0,'m'), (1,0,10,'n'), (2,0,5,'o'), (3,0,7,'p');
+SELECT a, MAX(b),
+(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b + 0)) as test 
+FROM t1 GROUP BY a;
+a	MAX(b)	test
+1	9	m
+2	3	h
+3	4	i
+SELECT a x, MAX(b),
+(SELECT t.c FROM t1 AS t WHERE x=t.a AND t.b=MAX(t1.b + 0)) as test
+FROM t1 GROUP BY a;
+x	MAX(b)	test
+1	9	m
+2	3	h
+3	4	i
+SELECT a, AVG(b),
+(SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=AVG(t1.b)) AS test
+FROM t1 WHERE t1.d=0 GROUP BY a;
+a	AVG(b)	test
+1	4.0000	d
+2	2.0000	g
+3	2.5000	NULL
+SELECT tt.a,
+(SELECT (SELECT c FROM t1 as t WHERE t1.a=t.a AND t.d=MAX(t1.b + tt.a)
+LIMIT 1) FROM t1 WHERE t1.a=tt.a GROUP BY a LIMIT 1) as test 
+FROM t1 as tt;
+a	test
+1	n
+1	n
+1	n
+1	n
+1	n
+1	n
+1	n
+2	o
+2	o
+2	o
+2	o
+3	p
+3	p
+3	p
+3	p
+3	p
+SELECT tt.a,
+(SELECT (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.d=MAX(t1.b + tt.a)
+LIMIT 1)
+FROM t1 WHERE t1.a=tt.a GROUP BY a LIMIT 1) as test 
+FROM t1 as tt GROUP BY tt.a;
+a	test
+1	n
+2	o
+3	p
+SELECT tt.a, MAX(
+(SELECT (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.d=MAX(t1.b + tt.a)
+LIMIT 1)
+FROM t1 WHERE t1.a=tt.a GROUP BY a LIMIT 1)) as test 
+FROM t1 as tt GROUP BY tt.a;
+a	test
+1	n
+2	o
+3	p
+DROP TABLE t1;