SQL 获取下午上午

--方法一：select 	sum(case		when (datepart(hour,pretime)>0 and datepart(hour,pretime)<12) then 1		else 0 end	) as 上午,	sum(case		when (datepart(hour,pretime)>12 and datepart(hour,pretime)<23) then 1		else 0 end	)as 下午	from preorder		where			pretime>'2011-2-1'			and pretime<'2011-7-7'--方法二：select t =  datepart(Hour,pretime) from preorder   >12下午。=<12上午--上午：if not (select object_id('Tempdb..#temp')) is null 	drop table #temp	select datepart(Hour,pretime) as num	into #temp	from preorder	go	select count(*) from #temp	where num>0 and num <13--下午：if not (select object_id('Tempdb..#temp')) is null 	drop table #temp	select datepart(Hour,pretime) as num	into #temp	from preorder	go	select count(*) from #temp	where num>12		

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