189 8069 5689
将两条查询语句作为子查询的一部分连表.
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select t1.count1+t2.count2 as 'countSum',t1.branch
(select count as count1, branch from table1 group by branch)t1
(select count as count2, branch from table2 group by branch)t2 on t1.branch =t2.branch
这种写法有一个潜在的限制,t1中的branch 必须包含t2,所以你的需求一般这么写:
select sum(counts)counts,branch
from(select * from(select count as counts, branch from table1 group by branch)t1
union
select * from(select count as counts, branch from table2 group by branch )t1)t
group by branch
----新建登录角色用户：
use master
exec sp_addlogin 'lx','123',['pubs']--新建登录lx,密码123, [默认数据库pubs]
use pubs
go
exec sp_grantdbaccess 'lx','slx'--为pubs添加一个用户(角色为public)
exec sp_addrolemember db_owner ,slx--将slx添加到db_owner角色组
# 注：可合并做一步 :
use pubs
exec sp_adduser lx,slx,db_owner
----------另外可以搞一个sa这样的牛逼账户，权限很高，你自己测试吧
exec sp_addsrvrolemember 'lx','sysadmin'--以sa登录执行，添加登录lx到system administrators中
嵌套比较多，你慢慢看。
select D.address, D.time, D.value
from (select A.address, A.time, A.value
from A
union
select B.address, B.time, B.value
from B) D,
(select C.Address, max(C.time) as maxTime
from (select A.address, A.time, A.value
from A
union
select B.address, B.time, B.value
from B) C
group by C.address) E
where D.address = E.address
and D.time = E.maxTime