sql_union.cc, sql_select.cc:

  Code clean-up
sql_union.cc, union.test, union.result:
  A fix for a bug #978.
  This enables that NULL's can be entered into UNION's result set,
  although first SELECT columns are NOT NULL.
  This is also a start of fixing UNION's properly regarding type
  acceptance.
sql_select.cc:
  A commit for my second July SPRINT task


mysql-test/r/union.result:
  A fix for a bug #978.
  
  This enables that NULL's can be entered into UNION's result set,
  although first SELECT columns are NOT NULL.
  
  This is also a start of fixing UNION's properly regarding type
  acceptance.
mysql-test/t/union.test:
  A fix for a bug #978.
  
  This enables that NULL's can be entered into UNION's result set,
  although first SELECT columns are NOT NULL.
  
  This is also a start of fixing UNION's properly regarding type
  acceptance.
sql/sql_select.cc:
  Code clean-up
sql/sql_union.cc:
  Code clean-up

1 files changed, 6 insertions, 10 deletions

diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index bd97a68e2d3..fae6810bab0 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -154,8 +154,6 @@ int st_select_lex_unit::prepare(THD *thd, select_result *sel_result,
       goto err;
     List_iterator<Item> it(select_cursor->item_list);	
     Item *item;
-    while((item=it++))
-      item->maybe_null=1;
     item_list= select_cursor->item_list;
     select_cursor->with_wild= 0;
     if (setup_ref_array(thd, &select_cursor->ref_pointer_array, 
@@ -166,6 +164,12 @@ int st_select_lex_unit::prepare(THD *thd, select_result *sel_result,
 		     item_list, 0, 0, 1))
       goto err;
     t_and_f= 1;
+    while((item=it++))
+    {
+      item->maybe_null=1;
+      if (item->type() == Item::FIELD_ITEM)
+	((class Item_field *)item)->field->table->maybe_null=1;
+    }
   }
 
   tmp_table_param.field_count=item_list.elements;
@@ -249,7 +253,6 @@ err:
 
 int st_select_lex_unit::exec()
 {
-  int do_print_slow= 0;
   SELECT_LEX_NODE *lex_select_save= thd->lex.current_select;
   SELECT_LEX *select_cursor=first_select_in_union();
   DBUG_ENTER("st_select_lex_unit::exec");
@@ -317,7 +320,6 @@ int st_select_lex_unit::exec()
 	thd->lex.current_select= lex_select_save;
 	DBUG_RETURN(res);
       }
-      do_print_slow|= select_cursor->options;
     }
   }
   optimized= 1;
@@ -360,12 +362,6 @@ int st_select_lex_unit::exec()
 	Mark for slow query log if any of the union parts didn't use
 	indexes efficiently
       */
-      select_cursor->options= ((select_cursor->options &
-				~(QUERY_NO_INDEX_USED |
-				  QUERY_NO_GOOD_INDEX_USED)) |
-			       do_print_slow &
-			       (QUERY_NO_INDEX_USED |
-				QUERY_NO_GOOD_INDEX_USED));
     }
   }
   thd->lex.current_select= lex_select_save;