fixed left expression of IN/ALL/ANY subquery transformation support (BUG#8888)

mysql-test/r/subselect.result:
  result changing
  fixed last test
  test of transformation of left expression of subquery
mysql-test/t/subselect.test:
  fixed last test
  test of transformation of left expression of subquery
sql/item_subselect.cc:
  fixfields made for left part of IN/ALL/ANY subquery before calling cols() to detect type of transformation (scalar or row)
  similar action of both transformation moved to separate function
sql/item_subselect.h:
  optimised field initialization and new method

mysql-test/r/subselect.result

@@ -2128,7 +2128,7 @@ drop table t1;
 create table t1 (a1 int);
 create table t2 (b1 int);
 select * from t1 where a2 > any(select b1 from t2);
-ERROR 42S22: Unknown column 'a2' in 'scalar IN/ALL/ANY subquery'
+ERROR 42S22: Unknown column 'a2' in 'IN/ALL/ANY subquery'
 select * from t1 where a1 > any(select b1 from t2);
 a1
 drop table t1,t2;
@@ -2267,4 +2267,12 @@ pass	userid	parentid	parentgroup	childid	groupname	grouptypeid	crse	categoryid	c
 1	5141	12	group2	12	group2	5	1	1	87	Oct04
 1	5141	12	group2	12	group2	5	1	2	88	Oct04
 1	5141	12	group2	12	group2	5	1	2	89	Oct04
-drop table if exists t1, t2, t3, t4, t5;
+drop table t1, t2, t3, t4, t5;
+create table t1 (a int);
+insert into t1 values (1), (2), (3);
+SELECT 1 FROM t1 WHERE (SELECT 1) in (SELECT 1);
+1
+1
+1
+1
+drop table t1;

mysql-test/t/subselect.test

@@ -1438,8 +1438,9 @@ select 1 = ALL (select 1 from t1 where 1 = xx ), 1 as xx;
 select 1 = ALL (select 1 from t1 where 1 = xx ), 1 as xx from DUAL;
 drop table t1;
 
+#
 # Test for BUG#8218
-
+#
 CREATE TABLE t1 (
   categoryId int(11) NOT NULL,
   courseId int(11) NOT NULL,
@@ -1536,5 +1537,12 @@ join
 group by 
   groupstuff.groupname, colhead , t2.courseid;
 
-drop table if exists t1, t2, t3, t4, t5;
+drop table t1, t2, t3, t4, t5;
 
+#
+# Transformation in left expression of subquery (BUG#8888)
+#
+create table t1 (a int);
+insert into t1 values (1), (2), (3);
+SELECT 1 FROM t1 WHERE (SELECT 1) in (SELECT 1);
+drop table t1;

sql/item_subselect.h

@@ -220,8 +220,8 @@ public:
 
   Item_in_subselect(Item * left_expr, st_select_lex *select_lex);
   Item_in_subselect()
-    :Item_exists_subselect(), abort_on_null(0), transformed(0), upper_item(0)
-     
+    :Item_exists_subselect(), optimizer(0), abort_on_null(0), transformed(0),
+     upper_item(0)
   {}
 
   subs_type substype() { return IN_SUBS; }
@@ -232,8 +232,8 @@ public:
     was_null= 0;
   }
   trans_res select_transformer(JOIN *join);
-  trans_res single_value_transformer(JOIN *join,
-				     Comp_creator *func);
+  trans_res select_in_like_transformer(JOIN *join, Comp_creator *func);
+  trans_res single_value_transformer(JOIN *join, Comp_creator *func);
   trans_res row_value_transformer(JOIN * join);
   longlong val_int();
   double val();