keep old engine & JOIN if we changed subquery Item (Bug #3646)

mysql-test/r/subselect.result:
  ALL/ANY test
mysql-test/t/subselect.test:
  ALL/ANY test
sql/item_subselect.cc:
  keep old engine & JOIN if we changed subquery Item, which allow avoid second all SELECT items fix_fields call with pervios clean up (because of second setup_tables which remove table->key_use and maybe something else)
  keep list when we change Item in SELECT list
  processing inserted max/min function (now JOIN::prepare will be called only once)
  methods of changing item for subselect engines
sql/item_subselect.h:
  change item & results procedure
sql/item_sum.cc:
  Item_sum_hybrid::clear moved to .cc file (to keep .h clean and to make inserving/removing debug info easy)
sql/item_sum.h:
  Item_sum_hybrid::clear moved to .cc file (to keep .h clean and to make inserving/removing debug info easy)
sql/sql_lex.cc:
  note about new method
sql/sql_lex.h:
  method for changing result of UNION JOINs
sql/sql_select.cc:
  method for changing result in JOIN
sql/sql_select.h:
  method for changing result in JOIN
sql/sql_union.cc:
  method for changing result in JOIN

1 files changed, 4 insertions, 0 deletions

diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 6d8f5353695..364781de362 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -290,6 +290,7 @@ public:
   virtual table_map upper_select_const_tables()= 0;
   static table_map calc_const_tables(TABLE_LIST *);
   virtual void print(String *str)= 0;
+  virtual int change_item(Item_subselect *si, select_subselect *result)= 0;
 };
 
 
@@ -313,6 +314,7 @@ public:
   void exclude();
   table_map upper_select_const_tables();
   void print (String *str);
+  int change_item(Item_subselect *si, select_subselect *result);
 };
 
 
@@ -332,6 +334,7 @@ public:
   void exclude();
   table_map upper_select_const_tables();
   void print (String *str);
+  int change_item(Item_subselect *si, select_subselect *result);
 };
 
 
@@ -360,6 +363,7 @@ public:
   void exclude();
   table_map upper_select_const_tables() { return 0; }
   void print (String *str);
+  int change_item(Item_subselect *si, select_subselect *result);
 };