取不同用户的最新数据

取最新数据很容易，select top  10 * from tb order by id desc 

 

但是要取不同用户的最新数据，就是保证这些数据中不会出现同个用户1条以上的数据

 

select top 10 * from tb a where not exists(select 1 from tb where username=a.username and bpostdate>a.bpostdate) 

 

select top 10 ID,UserName,BTypeID,BTitle,BHPic,BPostDate,LanguageID,BCompanyName,UserType,BRecommend from Business a where BState=1 and BOffline=0 andGetDate() between BPostDate and BValidate and userType>0 and not exists(select 1 from Business where UserName=a.UserName and BPostDate>a.BPostDate)order by userType desc,BPostDate desc

 

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