select a.*,c.cost
from T_xiaoshoumingxi a inner join T_xiaoshou b on a.xsid=b.sid
left join T_Caigoumingxi c on c.sid = a.cgmxid and c.pinming = a.pinming and b.leibie ='在库'
from T_xiaoshoumingxi a inner join T_xiaoshou b on a.xsid=b.sid
left join T_Caigoumingxi c on c.sid = a.cgmxid and c.pinming = a.pinming and b.leibie ='在库'
from T_xiaoshoumingxi a inner join T_xiaoshou b on a.xsid=b.sid
left join T_Caigoumingxi c on c.sid = a.cgmxid and c.pinming = a.pinming and b.leibie ='在库'
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....
select a.sid
,a.xid
,a.sex
,a.cgmxid
,pingming = (case when b.leibie = '在库' and a.cgmxid <> 0 then c.pinming else a.pinming end)
,zhongliang = (case when b.leibie = '在库' and a.cgmxid <> 0 then c.zhongliang else a.zhongliang end)
,成本 = (case when b.leibie = '委托' and a.cgmxid = 0 then 0 else b.cost end)
from T_xiaoshoumingxi a
join T_xiaoshou b on a.xsid = b.sid
join T_Caigoumingxi c on a.cgmxid = c.sid