diff --git a/library/Icinga/Data/Db/DbQuery.php b/library/Icinga/Data/Db/DbQuery.php
index f269cd138..aa8acf601 100644
--- a/library/Icinga/Data/Db/DbQuery.php
+++ b/library/Icinga/Data/Db/DbQuery.php
@@ -150,7 +150,7 @@ class DbQuery extends SimpleQuery
             && $this->getDatasource()->getDbType() === 'pgsql'
             && $select->getPart(Zend_Db_Select::DISTINCT) === true) {
             foreach ($this->getOrder() as $fieldAndDirection) {
-                if (array_search($fieldAndDirection[0], $this->columns) === false) {
+                if (array_search($fieldAndDirection[0], $this->columns, true) === false) {
                     $this->columns[] = $fieldAndDirection[0];
                 }
             }