HostgroupQuery: Add query column `instance_name'

refs #9943

modules/monitoring/library/Monitoring/Backend/Ido/Query/HostgroupQuery.php

@@ -17,6 +17,9 @@ class HostgroupQuery extends IdoQuery
      * {@inheritdoc}
      */
     protected $columnMap = array(
+        'instances' => array(
+            'instance_name' => 'i.instance_name'
+        ),
         'hostgroups' => array(
             'hostgroup'         => 'hgo.name1 COLLATE latin1_general_ci',
             'hostgroup_alias'   => 'hg.alias COLLATE latin1_general_ci',
@@ -126,6 +129,18 @@ class HostgroupQuery extends IdoQuery
         );
     }
 
+    /**
+     * Join instances
+     */
+    protected function joinInstances()
+    {
+        $this->select->join(
+            array('i' => $this->prefix . 'instances'),
+            'i.instance_id = hg.instance_id',
+            array()
+        );
+    }
+
     /**
      * {@inheritdoc}
      */

modules/monitoring/library/Monitoring/DataView/Hostgroup.php

@@ -14,6 +14,7 @@ class Hostgroup extends DataView
     public function getColumns()
     {
         return array(
+            'instance_name',
             'hostgroup_alias',
             'hostgroup_name'
         );