From b7f0270a242e346c35ec250e9388c38eff15a83e Mon Sep 17 00:00:00 2001
From: Eric Lippmann <eric.lippmann@icinga.com>
Date: Wed, 4 Jul 2018 15:29:22 +0200
Subject: [PATCH] Use SELECT 1 for subquery filters

refs #2934
---
 .../library/Monitoring/Backend/Ido/Query/IdoQuery.php        | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/modules/monitoring/library/Monitoring/Backend/Ido/Query/IdoQuery.php b/modules/monitoring/library/Monitoring/Backend/Ido/Query/IdoQuery.php
index 1c5b331a3..62ae9b212 100644
--- a/modules/monitoring/library/Monitoring/Backend/Ido/Query/IdoQuery.php
+++ b/modules/monitoring/library/Monitoring/Backend/Ido/Query/IdoQuery.php
@@ -611,7 +611,10 @@ abstract class IdoQuery extends DbQuery
 
         $subQuery
             ->setFilter($subQueryFilter)
-            ->clearGroupingRules();
+            ->clearGroupingRules()
+            ->select()
+            ->reset('columns')
+            ->columns([new Zend_Db_Expr('1')]);
 
         // EXISTS is the column name because without any column $this->isCustomVar() fails badly otherwise.
         // Additionally it bypasses the non-required optimizations made by our filter rendering implementation.