Mysql 生成订单流水号

原文转载地址

http://blog.csdn.net/dengsilinming/article/details/8488626#insertcode

mysql版本说明：mysql5.5

原文中sql语句报错，下面是测验通过的。

DELIMITER // 
CREATE PROCEDURE `generate_orderNo`(in orderNamePre char(2), in num int, out newOrderNo varchar(25))  
BEGIN  
  DECLARE currentDate varCHAR (15) ;    
  DECLARE maxNo INT DEFAULT 0 ; 
  DECLARE oldOrderNo VARCHAR (25) DEFAULT '' ;
    
  if num = 8 then   
    SELECT DATE_FORMAT(NOW(), '%Y%m%d') INTO currentDate ; 
  elseif num = 14 then   
    SELECT DATE_FORMAT(NOW(), '%Y%m%d%H%i%s') INTO currentDate ; 
  else   
    SELECT DATE_FORMAT(NOW(), '%Y%m%d%H%i') INTO currentDate ;  
  end if ;  
    
  SELECT IFNULL(orderNo, '') INTO oldOrderNo   
  FROM test_orders   
  WHERE SUBSTRING(orderNo, 3, num) = currentDate   
    AND SUBSTRING(orderNo, 1, 2) = orderNamePre   
    and length(orderNo) = 7 + num  
  ORDER BY id DESC LIMIT 1 ; 
    
  IF oldOrderNo != '' THEN   
    SET maxNo = CONVERT(SUBSTRING(oldOrderNo, -5), DECIMAL) ;  
  END IF ;  
  SELECT   
    CONCAT(orderNamePre, currentDate,  LPAD((maxNo + 1), 5, '0')) INTO newOrderNo ; 
  SELECT   
    newOrderNo ;  
END

补充网友使用过程中提出的问题，具体内容如下：

1. 测试语句不好使，故重新调整为（按顺序执行）：

CALL `generate_orderNo`('SH', 12, @orderNo); 
INSERT INTO test_orders (orderNo, orderName) VALUES(@orderNo, '测试订单');

2. 新需求：“不加前缀，随机流水号为3位”，代码如下：

DELIMITER // 
CREATE PROCEDURE `generate_orderNo`(in num int, out newOrderNo varchar(25))  
BEGIN  
  DECLARE currentDate varCHAR (15) ;    
  DECLARE maxNo INT DEFAULT 0 ; 
  DECLARE oldOrderNo VARCHAR (25) DEFAULT '' ;
    
  if num = 8 then   
    SELECT DATE_FORMAT(NOW(), '%Y%m%d') INTO currentDate ; 
  elseif num = 14 then   
    SELECT DATE_FORMAT(NOW(), '%Y%m%d%H%i%s') INTO currentDate ; 
  else   
    SELECT DATE_FORMAT(NOW(), '%Y%m%d%H%i') INTO currentDate ;  
  end if ;  
    
  SELECT IFNULL(orderNo, '') INTO oldOrderNo   
  FROM test_orders   
  WHERE SUBSTRING(orderNo, 1, num) = currentDate   
    and length(orderNo) = 3 + num  
  ORDER BY id DESC LIMIT 1 ; 
    
  IF oldOrderNo != '' THEN   
    SET maxNo = CONVERT(SUBSTRING(oldOrderNo, -3), DECIMAL) ;  
  END IF ;  
  SELECT   
    CONCAT(currentDate,  LPAD((maxNo + 1),3, '0')) INTO newOrderNo ; 
  SELECT   
    newOrderNo ;  
end