两个关于周的sql自定义函数

两个关于周的sql自定义函数

2009年10月27日 星期二 下午 03:59

--得到指定日期本年对应的周序数，第一周为本年内以周日开始周 周日为一周的第一天 CREATE function WeekOfDay(@Date nvarchar(10)) returns nvarchar(7) as begin declare @DWofYearsDay tinyint,@WeekOfDay tinyint,@Year smallint set @Year=year(@Date) set @DWofYearsDay=DATEPART(dw,cast(@Year as nvarchar)+'0101') if @DWofYearsDay=1 set @WeekOfDay= DATEPART(ww,@Date) else set @WeekOfDay= DATEPART(ww,@Date)-1 if @WeekOfDay=0 begin set @Year=@Year-1 set @WeekOfDay=52 end return cast(@Year as nvarchar)+'-'+cast(@WeekOfDay as nvarchar) end --得到指定某年某周的最大日期，第一周为本年内以周日开始周 周日为一周的第一天 CREATE function MaxDayOfWeek(@Week nvarchar(7)) returns smalldatetime as begin declare @DWofYearsDay tinyint,@Weeks tinyint,@Year nvarchar(4),@MaxDayOfWeek smalldatetime,@Days smallint set @Year=left(@Week,4) set @Weeks=substring(@Week,6,2) set @DWofYearsDay=DATEPART(dw,@Year+'0101') if @DWofYearsDay=1 set @Days= @Weeks*7 else set @Days= @Weeks*7+(7-@DWofYearsDay) set @MaxDayOfWeek=DATEADD (d, @Days, @Year+'0101' ) return @MaxDayOfWeek end