diff --git a/modules/monitoring/library/Monitoring/Backend/Ido/Query/HostdowntimeQuery.php b/modules/monitoring/library/Monitoring/Backend/Ido/Query/HostdowntimeQuery.php
index 0e2b503d8..ec9cd569b 100644
--- a/modules/monitoring/library/Monitoring/Backend/Ido/Query/HostdowntimeQuery.php
+++ b/modules/monitoring/library/Monitoring/Backend/Ido/Query/HostdowntimeQuery.php
@@ -107,7 +107,7 @@ class HostdowntimeQuery extends IdoQuery
             'hgo.objecttype_id = ?',
             3
         );
-        $this->group('ho.name1');
+        $this->group(array('sd.scheduleddowntime_id', 'ho.name1'));
     }
 
     /**
@@ -183,6 +183,6 @@ class HostdowntimeQuery extends IdoQuery
             'so.objecttype_id = ?',
             2
         );
-        $this->group('ho.name1');
+        $this->group(array('sd.scheduleddowntime_id', 'ho.name1'));
     }
 }
diff --git a/modules/monitoring/library/Monitoring/Backend/Ido/Query/ServicedowntimeQuery.php b/modules/monitoring/library/Monitoring/Backend/Ido/Query/ServicedowntimeQuery.php
index 55b8e466c..6d528ba73 100644
--- a/modules/monitoring/library/Monitoring/Backend/Ido/Query/ServicedowntimeQuery.php
+++ b/modules/monitoring/library/Monitoring/Backend/Ido/Query/ServicedowntimeQuery.php
@@ -112,7 +112,7 @@ class ServicedowntimeQuery extends IdoQuery
             'hgo.objecttype_id = ?',
             3
         );
-        $this->group(array('so.name2', 'so.name1'));
+        $this->group(array('sd.scheduleddowntime_id', 'so.name2', 'so.name1'));
     }
 
     /**
@@ -166,7 +166,7 @@ class ServicedowntimeQuery extends IdoQuery
             'sgo.objecttype_id = ?',
             4
         );
-        $this->group(array('so.name2', 'so.name1'));
+        $this->group(array('sd.scheduleddowntime_id', 'so.name2', 'so.name1'));
     }
 
     /**