sql 问题,,????

Question

/*
返回时间区域代码
*/
CREATE  FUNCTION [dbo].[GetCheckOnCode] 
(
@time VARCHAR(50)
)  
RETURNS VARCHAR(50)
AS  
BEGIN 
DECLARE @str VARCHAR(50)
DECLARE @D SMALLDATETIME
SET @D=CONVERT(SMALLDATETIME,@time,8)
IF DATEDIFF(SS,'00:00:00',@D)>=0 AND DATEDIFF(SS,'12:00:00',@D)<=0
SET @str='time1'
ELSE IF DATEDIFF(SS,'12:00:00',@D)>=0 AND DATEDIFF(SS,'17:00:00',@D)<=0
SET @str='time2'
ELSE IF DATEDIFF(SS,'17:00:00',@D)>=0 AND DATEDIFF(SS,'23:00:00',@D)<=0
SET @str='time3'
ELSE
SET @str='time4'
RETURN @str
END
gocreate table t1(no1 varchar(10),datetime1 datetime)
go
insert t1 values('001','2007-03-04 07:50')
insert t1 values('001','2007-03-04 13:25')
insert t1 values('001','2007-03-04 17:50')
insert t1 values('002','2007-03-04 07:50')
insert t1 values('002','2007-03-04 13:22')
insert t1 values('002','2007-03-04 17:56')
goselect * from t1
go
select no1,[dd],
[time1]=max(case when tag='time1' then tt end),
[time2]=max(case when tag='time2' then tt end),
[time3]=max(case when tag='time3' then tt end)
from (
select no1,[dd]=CONVERT(VARCHAR(10),datetime1,120),[tt]=CONVERT(VARCHAR(10),datetime1,8),
[tag]=[dbo].[GetCheckOnCode](CONVERT(VARCHAR(10),datetime1,8))
from t1
) t
group by no1,[dd]
godrop table t1
go