support of simple row subselects (SCRUM)

mysql-test/r/subselect.result:
  test of simple row subselect
  fixed table droping
mysql-test/t/subselect.test:
  test of simple row subselect
  fixed table dropimg
sql/item.cc:
  Item_cache_str fixed to correctly store NULL and copy string value
sql/item.h:
  Item_cache_str fixed to correctly store NULL and copy string value
sql/item_cmpfunc.cc:
  support of simple row subselects
sql/item_subselect.cc:
  support of simple row subselects
sql/item_subselect.h:
  support of simple row subselects
sql/sql_class.cc:
  support of simple row subselects

1 files changed, 3 insertions, 2 deletions

diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 50164aed342..0b12a34ebfb 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -931,8 +931,9 @@ bool select_singleval_subselect::send_data(List<Item> &items)
     DBUG_RETURN(0);
   }
   List_iterator_fast<Item> li(items);
-  Item *val_item= li++;                   // Only one (single value subselect)
-  it->store(val_item);
+  Item *val_item;
+  for (uint i= 0; (val_item= li++); i++)
+    it->store(i, val_item);
   it->assigned(1);
   DBUG_RETURN(0);
 }