MySQL 存储过程，参数无效，求解

    DROP PROCEDURE IF EXISTS market.app_get_list;
    DELIMITER //

    CREATE PROCEDURE market.app_get_list(IN orders VARCHAR(20), IN type TINYINT, IN offset INT, IN rows INT)
    BEGIN
        DECLARE done INT DEFAULT 0;
        DECLARE pack VARCHAR(40);
        DECLARE packages CURSOR FOR SELECT DISTINCT package FROM market_app ORDER BY orders DESC LIMIT offset, rows;
        DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; 

    OPEN packages;

    REPEAT
        FETCH packages INTO pack;
        IF NOT done THEN
            SELECT * FROM market_app WHERE package = pack ORDER BY versioncode DESC LIMIT 1;
        END IF;
    UNTIL done END REPEAT;

    CLOSE packages;
END//

    DELIMITER ;

现在参数orders不起作用，麻烦懂的人帮忙修改下，谢谢哈。