doSelectStmt in symfony 1.2

doSelectStmt in symfony 1.2

        $cd = new Criteria();
        $cd->clearSelectColumns();
        $cd->addSelectColumn('SUM(' . TablePeer::QTY . ') as sumqty');
        $stmt = TablePeer::doSelectStmt($cd);
        $row = $stmt->fetch(PDO::FETCH_ASSOC);
        echo $row['sumqty'];