帮助...一个小问题

[wansijei]

一个表.. 内有三个字段..
ID Num Direction
1 10 1
1 5 1
2 8 -1
1 5 -1
2 10 1

ID表示一个商品的ID号..NUM为这一次进/出账的数量..Direction为方向,,1就表示进账.-1表示出账..
我现在要账记每一种商品的进账.和出长数量..
如何写出来?
输出要是
ID INNuM OUTNum
1 15 5
2 10 8

InNum为进账 OutNum为出账
谢谢了

[txlicenhe]

Select ID,sum(case when direction = 1 then num else 0 end) as INNum,
sum(case when direction = -1 then num else 0 end) as OUTNum
from 表 group by ID

[txlicenhe]

or

Select ID,(select sum(num) where id = a.id and direction = 1) as INNum,
(select sum(num) where id = a.id and direction = -1) as OUTNum
from 表 a

[wansijei]

很正确..高手呀..呵.我给分了.