1 files changed, 4 insertions, 1 deletions
diff --git a/sql/filesort.cc b/sql/filesort.cc
index 27c4b962515..8bf9c648e82 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -450,7 +450,10 @@ static void make_sortkey(register SORTPARAM *param,
       {
 	if (field->is_null())
 	{
-	  bzero((char*) to,sort_field->length+1);
+	  if (sort_field->reverse)
+	    bfill(to,sort_field->length+1,(char) 255);
+	  else
+	    bzero((char*) to,sort_field->length+1);
 	  to+= sort_field->length+1;
 	  continue;
 	}