diff --git a/modules/monitoring/library/Monitoring/Backend/Ido/Query/NotificationhistoryQuery.php b/modules/monitoring/library/Monitoring/Backend/Ido/Query/NotificationhistoryQuery.php
index 8bbdc0751..1195161d3 100644
--- a/modules/monitoring/library/Monitoring/Backend/Ido/Query/NotificationhistoryQuery.php
+++ b/modules/monitoring/library/Monitoring/Backend/Ido/Query/NotificationhistoryQuery.php
@@ -26,15 +26,6 @@ class NotificationhistoryQuery extends IdoQuery
         )
     );
 
-    public function whereToSql($col, $sign, $expression)
-    {
-        if ($col === 'UNIX_TIMESTAMP(n.start_time)') {
-            return 'n.start_time ' . $sign . ' ' . $this->timestampForSql($this->valueToTimestamp($expression));
-        } else {
-            return parent::whereToSql($col, $sign, $expression);
-        }
-    }
-
     protected function joinBaseTables()
     {
         switch ($this->ds->getDbType()) {