SQLServer中计算周

	--本周最大值与最小值、平均值

	DECLARE @WeekMax float,@WeekMin float,@WeekAvg float,@AddDate varchar(20)

	DECLARE @WeekStart int,@WeekEnd int,@WeekCount int,@WeekStr varchar(12),@WeekNum int

	SET @AddDate = CAST(@Year as varchar(4)) + '-' + CAST(@Month as varchar(4)) + '-' + CAST(@Day as varchar(4))

	select @WeekCount=datename(week,@AddDate),@WeekStr=datename(weekday,@AddDate)

	select @WeekNum = case @WeekStr

				When '星期一' THEN 1

				When '星期二' THEN 2

				When '星期三' THEN 3

				When '星期四' THEN 4

				When '星期五' THEN 5

				When '星期六' THEN 6

				ELSE 7

			END

	SET @WeekStart = DATEADD([day],(0-(@WeekNum-1)),@AddDate)

	SET @WeekEnd = DATEADD([day],(7-@WeekNum),@AddDate)