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)