From 5be48fc923cf532837f9b072c33a9fad6c6e5257 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@netways.de>
Date: Thu, 3 Dec 2015 13:53:34 +0100
Subject: [PATCH] DbQuery: Do not call Zend_Db_Select::columns() unless it's
 necessary

This makes it possible to just use a DbQuery as "union container" without
ever calling from() on it.
---
 library/Icinga/Data/Db/DbQuery.php | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/library/Icinga/Data/Db/DbQuery.php b/library/Icinga/Data/Db/DbQuery.php
index f5b730dce..860b7fe25 100644
--- a/library/Icinga/Data/Db/DbQuery.php
+++ b/library/Icinga/Data/Db/DbQuery.php
@@ -153,7 +153,10 @@ class DbQuery extends SimpleQuery
             $select->group($group);
         }
 
-        $select->columns($this->columns);
+        if (! empty($this->columns)) {
+            $select->columns($this->columns);
+        }
+
         $this->applyFilterSql($select);
 
         if ($this->hasLimit() || $this->hasOffset()) {
@@ -333,7 +336,9 @@ class DbQuery extends SimpleQuery
         $this->applyFilterSql($count);
         $group = $this->getGroup();
         if ($this->useSubqueryCount || $group) {
-            $count->columns($this->columns);
+            if (! empty($this->columns)) {
+                $count->columns($this->columns);
+            }
             if ($group) {
                 $count->group($group);
             }