fixed bug in used_tables() report of left expression of IN subquery

fixed number of rows of external field reported to optimizer
added check of choosen key (checked left expression tag)
(SCRUM fix for simple IN optimisation)


mysql-test/r/subselect.result:
  new EXPLAIN results ufter fixing used_tables() of Item_cache
sql/item_cmpfunc.cc:
  fixed used_tables asignment
sql/item_subselect.cc:
  added left expression referenca tag
sql/item_subselect.h:
  fixed layout
sql/mysql_priv.h:
  left expression reference tag
sql/mysqld.cc:
  left expression reference tag
sql/sql_select.cc:
  checked left expression reference tag
  fixed number of rows in outer reference (it should be constant)

1 files changed, 2 insertions, 2 deletions

diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 68655d51521..c0171614fae 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -518,7 +518,7 @@ Item_in_subselect::single_value_transformer(JOIN *join,
     */
     expr= new Item_ref((Item**)optimizer->get_cache(), 
 		       (char *)"<no matter>",
-		       (char *)"<left expr>");
+		       (char *)in_left_expr_name);
 
     unit->dependent= 1;
   }
@@ -694,7 +694,7 @@ Item_in_subselect::row_value_transformer(JOIN *join,
       Item_bool_func2::eq_creator(new Item_ref((*optimizer->get_cache())->
 					       addr(i), 
 					       (char *)"<no matter>",
-					       (char *)"<left expr>"),
+					       (char *)in_left_expr_name),
 				  func);
     item= and_items(item, func);
   }