diff --git a/handlers/views_handler_filter_boolean_operator_string.inc b/handlers/views_handler_filter_boolean_operator_string.inc
index b49dde9..080ac50 100644
--- a/handlers/views_handler_filter_boolean_operator_string.inc
+++ b/handlers/views_handler_filter_boolean_operator_string.inc
@@ -30,6 +30,6 @@ class views_handler_filter_boolean_operator_string extends views_handler_filter_
     else {
       $where .= "<> ''";
     }
-    $this->query->add_where($this->options['group'], $where);
+    $this->query->add_where_expression($this->options['group'], $where);
   }
 }