diff --git a/includes/alerts.inc.php b/includes/alerts.inc.php
index accdd09a96..99ff66571d 100644
--- a/includes/alerts.inc.php
+++ b/includes/alerts.inc.php
@@ -67,7 +67,7 @@ function GetRules($device) {
 		$where .= " || alert_map.target = ?";
 		$params[] = 'g'.$group;
 	}
-	return dbFetchRows('SELECT alert_rules.* FROM alert_rules,alert_map WHERE (alert_rules.device_id = -1 || alert_rules.device_id = ? ) || ( alert_rules.id=alert_map.rule && ( alert_map.target = ? '.$where.' ) )',$params);
+	return dbFetchRows('SELECT alert_rules.* FROM alert_rules LEFT JOIN alert_map ON alert_rules.id=alert_map.rule WHERE (alert_rules.device_id = -1 || alert_rules.device_id = ? ) || ( alert_map.target = ? '.$where.' )',$params);
 }
 
 /**