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, 2 insertions, 8 deletions

diff --git a/mysql-test/r/subselect3.result b/mysql-test/r/subselect3.result
index 6a7a601ccf9..33e7fc54ed2 100644
--- a/mysql-test/r/subselect3.result
+++ b/mysql-test/r/subselect3.result
@@ -432,7 +432,7 @@ alter table t1 add index idx(oref,ie);
 explain select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	7	
-2	DEPENDENT SUBQUERY	t1	ref_or_null	idx	idx	10	t2.oref,func	4	Using where; Using index; Full scan on NULL key
+2	DEPENDENT SUBQUERY	t1	ref_or_null	idx	idx	10	test.t2.oref,func	4	Using where; Using index; Full scan on NULL key
 select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2;
 oref	a	Z
 ee	NULL	NULL
@@ -457,7 +457,7 @@ group by grp having min(ie) > 1) Z
 from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	7	
-2	DEPENDENT SUBQUERY	t1	ref	idx	idx	5	t2.oref	2	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ref	idx	idx	5	test.t2.oref	2	Using where; Using temporary; Using filesort
 select oref, a, 
 a in (select min(ie) from t1 where oref=t2.oref 
 group by grp having min(ie) > 1) Z 
@@ -661,12 +661,6 @@ SELECT * FROM t1 GROUP by t1.a
 HAVING (MAX(t1.b) > (SELECT MAX(t2.b) FROM t2 WHERE t2.c < t1.c
 HAVING MAX(t2.b+t1.a) < 10));
 a	b	c
-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 GROUP BY a;
-a	AVG(b)	test
-1	4.0000	NULL
-2	2.0000	k
-3	2.5000	NULL
 SELECT a,b,c FROM t1 WHERE b in (9,3,4) ORDER BY b,c;
 a	b	c
 1	3	c