MySQL生成-单据号不重复

需求生成一个单据编号

单据编号结构： “单据类型” + “日期” + “流水号”

例子 ： GD201605230000007

代码：

DELIMITER $$

CREATE

    PROCEDURE `yunzhi`.`auto_no`())

    BEGIN
    DECLARE v_timestr VARCHAR();
    DECLARE v_cnt INT;
    DECLARE rowcount BIGINT;

    -- 当前日期（8位短日期）
    SET v_timestr = DATE_FORMAT(NOW(), '%Y%m%d');
    SELECT CONCAT(billType,v_timestr) INTO v_timestr;

    ;
        ) WHERE timestr = v_timestr;

         THEN
            );
        END IF;

        ,)) AS sn
        FROM no_seq WHERE timestr = v_timestr;
    COMMIT;
    END$$

DELIMITER ;