mysql编号生成_MySQL

DELIMITER $$
CREATE DEFINER=`root`@`localhost` FUNCTION `get_workNo`() RETURNS varchar(45) CHARSET utf8
BEGIN
DECLARE newWorkNo varCHAR (45) ;
	DECLARE currentDate varCHAR (15) ;-- 当前日期,有可能包含时分秒 
	DECLARE maxNo INT DEFAULT 0 ;
	DECLARE oldWorkNo VARCHAR (25) DEFAULT '' ;-- 离现在最近的满足条件的订单编号 
	
	
	SELECT SUBSTRING(DATE_FORMAT(NOW(), '%Y%m'),3,6) INTO currentDate ;
	
	SELECT IFNULL(workNo, '') INTO oldWorkNo 
	 FROM operation_work 
	 WHERE SUBSTRING(workNo, 3, 4) = currentDate 
	ORDER BY id DESC LIMIT 1 ; -- 有多条时只显示离现在最近的一条 
	
	IF oldWorkNo != '' THEN 
	SET maxNo = CONVERT(SUBSTRING(oldWorkNo, -4), DECIMAL) ;-- SUBSTRING(oldOrderNo, -5)：订单编号如果不为‘‘截取订单的最后5位 
	END IF ;
	
	SELECT 
	CONCAT('TS', currentDate, LPAD((maxNo + 1), 4, '0')) INTO newWorkNo ;
	
RETURN newWorkNo;
END$$
DELIMITER ;

USE `it_system`;
DELIMITER $$
CREATE DEFINER=`root`@`localhost` TRIGGER `operation_work_BINS` BEFORE INSERT ON `operation_work` FOR EACH ROW
begin SET @workNo = get_workNo(); 
 set NEW.workNo=@workNo;
end