Mysql Fonksiyon Oluşturmak

DELIMITER $$
CREATE DEFINER=`root`@`localhost` FUNCTION `DENEME`(`id_no` INT(11)) RETURNS varchar(50) CHARSET utf8mb4
BEGIN
DECLARE UNAME VARCHAR(100);
SELECT k.ad AS kad INTO UNAME FROM kisi AS k WHERE id=id_no LIMIT 1;
RETURN UNAME;
END$$
DELIMITER ;