/**
* Build the sub query which is used when merging in
* repeat element records from their joined table into the one field.
* Overwritten in database join element to allow for building
* the join to the talbe containing the stored values required ids
*
* @since 2.1.1
*
* @return string sub query
*/
protected function buildQueryElementConcatId()
{
$str = parent::buildQueryElementConcatId();
$jointable = $this->getJoinModel()->getJoin()->table_join;
$dbtable = $this->actualTableName();
$db = JFactory::getDbo();
$table = $this->getListModel()->getTable();
$fullElName = $this->getFullName(false, true, false) . "_id";
$str .= ", (SELECT GROUP_CONCAT(" . $this->_element->name . " SEPARATOR '" . GROUPSPLITTER . "') FROM {$jointable} WHERE " . $jointable . ".parent_id = " . $table->db_primary_key . ") AS {$fullElName}";
return $str;
}
