求sql语句，刚才回答的不对,该如何处理_Sql Server

求sql语句，刚才回答的不对
现在有一张表，有人员编号，日期，时间三个字段,数据如下：

bh date time
1 20070809 08:00:00
1 20070809 09:00:00
1 20070809 17:00:00
1 20070810 07:00:00
2 20070809 08:00:00
3 20070910 08:00:00
现在要找出每个人每天 time最大值与最小值的差值，怎么写语句

------解决方案--------------------

SQL code

select bh,date, datediff(ms,date+' ' +max(time), date + ' ' + min(time))from tb  group by bh,date
------解决方案--------------------
SQL codecreate table #tt (bh varchar(10),[date] varchar(20),[time] varchar(20))insert into #tt select '1','20070809','08:00:00'union allselect '1','20070809','09:00:00'union allselect '1','20070809','17:00:00'union allselect '1','20070810','07:00:00'union allselect '2','20070809','08:00:00'union allselect '3','20070810','08:00:00'select bh,[date],datediff(minute,min([time]),max([time]))  '相差（分）' from #tt group by bh,[date] order by [date]