diff --git a/plugins/views_plugin_query_default.inc b/plugins/views_plugin_query_default.inc
index 7468dd9..444fe86 100644
--- a/plugins/views_plugin_query_default.inc
+++ b/plugins/views_plugin_query_default.inc
@@ -1322,7 +1322,7 @@ class views_plugin_query_default extends views_plugin_query {
     if (count($this->having)) {
       $this->has_aggregate = TRUE;
     }
-    elseif (!$this->has_aggregate) {
+    elseif (!$this->has_aggregate && isset($this->view->display_handler)) {
       // Allow 'GROUP BY' even no aggregation function has been set.
       $this->has_aggregate = $this->view->display_handler->get_option('group_by');
     }