Почему не выводиться с prestashop выборка из БД?

public static function getShiftFromOrderForEmail($id_order){
        $res = Db::getInstance(_PS_USE_SQL_SLAVE_)->getValue(
            'select  s.time_from
			from `'._DB_PREFIX_.'shift` as s
			join `'._DB_PREFIX_.'1c_orders` as c on c.id_shift = s.id_shift
			join `'._DB_PREFIX_.'orders` as o on o.id_order = c.id_order
			where o.id_order = '.(int)$id_order );


        $res2 = Db::getInstance(_PS_USE_SQL_SLAVE_)->getValue('select  s.time_from, s.time_to
											from ps_shift as s
											join ps_1c_orders as c on c.id_shift = s.id_shift
											join ps_orders as o on o.id_cart = c.id_c
											where o.id_order = 555'.(int)$id_order );


        $sql = new DbQuery();
        $sql->select('CONCAT(s.time_from, " - " ,s.time_to )');
        $sql->from('shift','s');
        $sql->innerJoin('1c_orders', 'c' , 'c.id_shift = s.id_shift')
        	$sql->innerJoin('orders', 'o' , 'o.id_order = c.id_order')
        	$sql->where('o.id_order = '.(int)$id_order);
        	$result = Db::getInstance()->getRow($sql);
 Db::getInstance()->getMsgError();
		return $result ? $result : 'none';
      


    }