请问： S Q L Server 两表关联查询问题
表data_merch :
id merchid merchmemo
---------------------
1 a b
2 c d
表data_bom
id fmerchid zmerchid demo
---------------------------
1 a x demo
2 z k demo
==========
现在要查询在data_merch里面的merchid在data_bom中（fmerchid,zmerchid）出现过的数据
=========
我写的 达不到效果：
select * from data_bom as a left join data_merch as b on a.zmerchid=b.merchid or a.fmerchid=b.merchid
=========
[解决办法]
不太明白楼主的意思 能否写出你希望查出来的数据
[解决办法]
你的查询结果是什么?是data_merch表中符合条件的内容还是???如果我理解得没错的话.你这样写:
select * from data_merch
where merechid in (select fmerchid from data_bom)
or merechid in (select zmerchid from data_bom)
[解决办法]
select *
from
data_bom as a
left join
data_merch as b
on
a.zmerchid=b.merchid
or a.fmerchid=b.merchid
where
b.merchid is not null
and b.merchid is not null
