表A
mc名称 ZH(存货)
A 900
B 867
表B
mc名称 QH(取货)
A 123
A 234
A 210
B 122
B 301
请用一条SQL语句将商品存货结果计算出来？



哪位大虾会？指点一下

怎么没人顶啊。。谁来教教我！

select aa.mc,sum(distinct aa.zh)-sum(bb.qh) as '现有存货' from A aa inner join B bb on aa.mc=bb.mc group by aa.mc

select mc,总数=sum(ZH) from
(select mc,zh from A
union all
select mc,zh from b1)B
group by mc

改正一下
select mc,总数=sum(zh) from
(select mc,zh from A
union all
select mc,zh from B)
group by mc

吐血.........
看错题目了!!不好意思

谢谢3楼那头猪。。我少加了个distinct~~

最好把inner join改成left join,要考虑存货中有的产品，但是没取过货物的,如果用inner join的话就会忽略库存中有的,但是没有被取过的

select * from a  left join b on a.name=b.name

豆芽就是厉害。。外连接都会了