如何判断一年中的某周是几月几号到几月同号

declare @tmpdate datetime
select @tmpdate=dateadd(week,19,'2007-01-01')

--起始日期:
select dateadd(day,-datepart(weekday,@tmpdate)+1,@tmpdate)
--截止日期:
select dateadd(day,7-datepart(weekday,@tmpdate),@tmpdate)