--- date_api_sql.inc	2010-08-13 04:37:07.000000000 +1000
+++ date_api_sql.inc	2011-03-30 11:06:59.000000000 +1100
@@ -252,9 +252,9 @@ class date_sql_handler {
         $granularity .= 'S';
         switch ($direction) {
           case 'ADD':
-            return "($field + INTERVAL '$count $granularity')";
+            return "($field + ($count * INTERVAL '1 $granularity'))";
           case 'SUB':
-            return "($field - INTERVAL '$count $granularity')";
+            return "($field - ($count * INTERVAL '1 $granularity'))";
         }
      }
      return $field;