采用先进先出原则对货物的库存进行处理
--貌似经常看到有人发帖，这次自己也在做类似的会员卡营销系统，里面有积分消费功能，也是采用先进先出原则，所以提供下本人的思路，算是起个抛砖引玉的作用。高手们有更好的方法顺便指教下，使得以后大家碰到类似的问题有个比较好的解决方案。--库存表
create table t(
id int identity(1,1),
name varchar(50),--商品名称
j int, --入库数量
c int, --出库数量
jdate datetime --入库时间
)
insert into t(name,j,c,jdate) select'A',100,0,'2007-12-01'
insert into t(name,j,c,jdate) select'A',200,0,'2008-01-07'
insert into t(name,j,c,jdate) select'B',320,0,'2007-12-21'
insert into t(name,j,c,jdate) select'A',100,0,'2008-01-15'
insert into t(name,j,c,jdate) select'B',90,0,'2008-02-03'
insert into t(name,j,c,jdate) select'A',460,0,'2008-02-01'
insert into t(name,j,c,jdate) select'A',510,0,'2008-03-01'
go
create proc wsp
@name varchar(50),--商品名称
@cost int --销售量
as
--先得出该货物的库存是否够
declare @spare float --剩余库存
select @spare=sum(j)-sum(c) from t where name=@name
if(@spare>=@cost)
begin
--根据入库日期采用先进先出原则对货物的库存进行处理
update t set c=
case when (select @cost-isnull(sum(j),0)+isnull(sum(c),0) from t where name=@name and jdate<=a.jdate and j!=c)>=0
then a.j
else
case when (select @cost-isnull(sum(j),0)+isnull(sum(c),0) from t where name=@name and jdate<a.jdate and j!=c)<0 then 0
else (select @cost-isnull(sum(j),0)+isnull(sum(c),0)+a.c from t where name=@name and jdate<a.jdate and j!=c)
end
end
from t a where name=@name and j!=c
end
else
raiserror('库存不足',16,1)
return
go
--测试：
exec wsp @name='A',@cost=180
select * from t
--drop table t
--drop proc wsp
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