一个会员卡使用问题
有一数据表存储用户的会员卡信息,有列(主键id,用户Id,剩余的钱,过期时间)
Id UserId RemainingMoney ExpireDate
1 1 3.5 2012-5-1
2 2 3.5 2012-5-1
3 1 4.0 2012-6-2
4 1 5.0 2012-6-1
要求1
输入参数@UserId,扣款金额@Money
按过期时间的顺序,输出满足指定金额@Money的记录,比如输入@UserId=1,@Money=6,则返回id为1和4的记录,因为这两条记录的总额足够支付6,而且比记录3先过期。
要求2
执行扣款操作,比如上面的条件,记录1更新为0,记录4更新为2.5
目前使用游标解决,一条一条的处理,但该操作比较频繁,不知是否有更好的办法?
[解决办法]
--没用游标,你可以测试一下declare @T table (Id int,UserId int,RemainingMoney numeric(2,1),ExpireDate datetime)insert into @Tselect 1,1,3.5,'2012-5-1' union allselect 2,2,3.5,'2012-5-1' union allselect 3,1,4.0,'2012-6-2' union allselect 4,1,5.0,'2012-6-1'--给参数赋值declare @userid int set @userid=1declare @money int set @money=4declare @j datetimedeclare @k numeric(2,1);with maco as ( select * from @T where UserId=@userid),maco1 as( select *,总金额=(select sum(RemainingMoney) from maco where ExpireDate<=a.ExpireDate) from maco a) select top 1 @j=ExpireDate,@k=总金额-@money from maco1 where 总金额>=@money order by ExpireDateupdate @T set RemainingMoney=@k where ExpireDate=@j and UserId=@userid update @T set RemainingMoney=0 where UserId=@userid and ExpireDate<@j select * from @T /*Id UserId RemainingMoney ExpireDate----------- ----------- --------------------------------------- -----------------------1 1 0.0 2012-05-01 00:00:00.0002 2 3.5 2012-05-01 00:00:00.0003 1 4.0 2012-06-02 00:00:00.0004 1 4.5 2012-06-01 00:00:00.000*/