public function getSelectCountSql()
 {
     $countSelect = parent::getSelectCountSql();
     if ($this->_allowDisableGrouping) {
         $countSelect->reset(Zend_Db_Select::COLUMNS);
         $countSelect->reset(Zend_Db_Select::GROUP);
         $countSelect->columns('COUNT(DISTINCT ' . $this->getCountAttribute() . ')');
     }
     return $countSelect;
 }