Fixed LP bug #800518.

The function simple_pred did not take into account that a multiple equality
could include ref items (more exactly items of the class Item_direct_view_ref).
It caused crashes for queries over derived tables or views if the
min/max optimization could be applied to these queries.

1 files changed, 5 insertions, 3 deletions

diff --git a/sql/opt_sum.cc b/sql/opt_sum.cc
index 965eb853471..78cb2fa8210 100644
--- a/sql/opt_sum.cc
+++ b/sql/opt_sum.cc
@@ -494,11 +494,13 @@ bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
     /* MULT_EQUAL_FUNC */
     {
       Item_equal *item_equal= (Item_equal *) func_item;
+      if (!(args[1]= item_equal->get_const()))
+        return 0;
       Item_equal_fields_iterator it(*item_equal);
-      args[0]= it++;
-      if (it++)
+      if (!(item= it++))
         return 0;
-      if (!(args[1]= item_equal->get_const()))
+      args[0]= item->real_item();
+      if (it++)
         return 0;
     }
     break;