读取用户列表的时候，同时读出该用户最新发布的一个帖子。

select *, 

       帖子=(select top 1 Title from Dx_BBS where UserID=a.UserID order by id desc)

    from Dx_User  a

 

select *, 

       帖子=(select top 1 Title from Dx_BBS where UserID=a.UserID' order by id desc)

    from Dx_User  a

select *

from Dx_Use as a

inner join Dx_BBS as b on b.UserID=a.UserID

where not exists(select 1 from Dx_BBS where UserID=b.UserID and ID>b.ID)

select * 

from Dx_User as a cross apply(select top 1 * from Dx_BBS where UserID=a.UserID order by ID desc) as b