select * from tb where UserID=1 or IsShared='Y'

------解决方案--------------------
探讨


这句我就看不懂了引用:
因为还有一个列为ShowID,
当IsShared为N时，只能是UserID&ShowID可查到
那是不是要改成如下:

select * from tb where UserID=1 or IsShared='Y' and ShowID=2 or IsShared='Y'

这样呢？？


------解决方案--------------------
SQL code
use Tempdb
go
--> --> 
 
if not object_id(N'Tempdb..#T') is null
    drop table #T
Go
Create table #T([Id] int,[UserID] int,[IsShared] nvarchar(1))
Insert #T
select 1,1,N'N' union all
select 2,1,N'Y' union all
select 3,2,N'N' union all
select 4,2,N'Y' union all
select 5,3,N'N' union all
select 6,3,N'Y'
Go
DECLARE @userID INT
SET @userid=1


Select * 
from #T AS a
WHERE UserID=@userid OR [IsShared]='Y'

/*
Id    UserID    IsShared
1    1    N
2    1    Y
4    2    Y
6    3    Y
*/

------解决方案--------------------
1:熟悉 AND OR 的用法
2:在相同关系 的地方 用括号括起来
select * from tb where UserID=1 or showid=2 or IsShared='Y'

select * from tb where UserID=1 AND showid=2 or IsShared='Y'


select * from tb where (UserID=1 AND showid=2) or IsShared='Y'
select * from tb where UserID=1 AND (showid=2 or IsShared='Y')
分别试试 再理解一下就可灵活使用