--当天：

select * from T_news where datediff(day,addtime,getdate())=0

--最近三天：

select * from T_news where datediff(day,addtime,getdate())<= 2 and datediff(day,addtime,getdate())>= 0

--本周：

select * from T_news WHERE (DATEPART(wk, addtime) = DATEPART(wk, GETDATE())) AND (DATEPART(yy, addtime) = DATEPART(yy, GETDATE()))

--注意：此时不能用 datediff 差值为7,因为，datediff只表示间隔数

--本月：

select * from T_news WHERE (DATEPART(yy, addtime) = DATEPART(yy, GETDATE())) AND (DATEPART(mm, addtime) = DATEPART(mm, GETDATE()))

--最近一个月：

select * from T_news WHERE (DATEPART(yy, addtime) = DATEPART(yy, GETDATE()))

AND ((DATEPART(mm, addtime) = DATEPART(mm, GETDATE())) OR (31-DATEPART(DD,addtime)+DATEPART(DD, GETDATE()))<=31)

--本季度：

select * from T_news where DATEPART(qq, addtime) = DATEPART(qq, GETDATE()) and DATEPART(yy, addtime) = DATEPART(yy, GETDATE())