/*T-SQL: 15 个与日期时间相关的自定义函数(UDF),周日作为周的最后一天,均不受 @@DateFirst、语言版本影响都是从老文章里收集或提炼出来的!提示:(@@Datefirst + datepart(weekday,@Date)) % 7 判断周几是最保险的! 与 @@DateFirst 无关,与语言版本无关@@DateFirst 可能会导致 datepart(weekday,@Date) 不一样!无论 @@DateFirst 等于几,无论是什么语言版本的 SQL Server 下面永远恒成立!(@@Datefirst + datepart(weekday,@Date)): 2、3、4、5、6、0、1 分别代表 周一 到 周日-- */

create function udf_GetAge(@StartDate datetime,@EndDate datetime)returns integer-- 返回精确年龄 select dbo.udf_GetAge(\'1949-10-01\',getdate())beginreturn datediff(year,@StartDate,@EndDate) - case when datediff(day,dateadd(year,datediff(year,@StartDate,@EndDate),@StartDate),@EndDate) >= 0 then 0 else 1 endend

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create function udf_DaysOfYearByDate(@Date datetime)RETURNS integer-- 返回年的天数 可判断 平(365)、润(366) 年beginreturn datediff(day,dateadd(year,datediff(year,0,@Date),0),dateadd(year,datediff(year,0,@Date )+1,0))end

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create function udf_DaysOfYear(@Year integer)RETURNS integer-- 返回年的天数 可判断 平(365)、润(366) 年beginreturn datediff(day,dateadd(year,@year - year(0),0),dateadd(year,@year - year(0) + 1,0))end

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create function udf_HalfDay(@Date datetime)returns datetime-- 返回 @Date 是 上午 返回 @Date 的零点,@Date 是 下午 返回 @Date 的十二点asbeginreturn case when datepart(hour,@Date) < 12 then dateadd(day,datediff(day,0,@Date),0) --上午归到 零点 else dateadd(hour,12,dateadd(day,datediff(day,0,@Date),0)) --下午归到 十二点 endend

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create function udf_WeekDiff(@StartDate datetime,@EndDate datetime)returns integer-- 返回 [@StartDate , @EndDate] 之间周数 周日是当周的最后一天beginreturn datediff(week,@StartDate,@EndDate) -- + 1 + case when (@@Datefirst + datepart(weekday,@StartDate)) % 7 = 1 then 1 else 0 end - case when (@@Datefirst + datepart(weekday,@EndDate)) % 7 = 1 then 1 else 0 endend

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create function udf_WeekOfMonth(@Date datetime)-- 返回 @Date 是所在月的第几周 周日是当周的最后一天returns integerasbeginreturn datediff(week ,case when (@@Datefirst + datepart(weekday,dateadd(month,datediff(month,0,@Date),0))) % 7 = 1 then dateadd(month,datediff(month,0,@Date),0) - 1 else dateadd(month,datediff(month,0,@Date),0) end ,case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 1 then @Date-1 else @Date end ) + 1end

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create function udf_WeekOfQuarter(@Date datetime)-- 返回 @Date 是所在季度的第几周 周日是当周的最后一天returns intasbeginreturn datediff(week ,case when (@@Datefirst + datepart(weekday,dateadd(Quarter,datediff(Quarter,0,@Date),0))) % 7 = 1 then dateadd(Quarter,datediff(Quarter,0,@Date),0) - 1 else dateadd(Quarter,datediff(Quarter,0,@Date),0) end ,case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 1 then @Date - 1 else @Date end ) + 1end

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create function udf_WeekOfYear(@Date datetime)-- 返回 @Date 是所在年的第几周 周日是当周的最后一天returns intasbeginreturn datediff(week ,case when (@@Datefirst + datepart(weekday,dateadd(day,0,datediff(day,0,dateadd(year,datediff(year,0,@Date),0))))) % 7 = 1 then dateadd(day,-1,dateadd(day,0,datediff(day,0,dateadd(year,datediff(year,0,@Date),0)))) else dateadd(day,0,datediff(day,0,dateadd(year,datediff(year,0,@Date),0))) --date 所在年的第一天 即: 一月一号 end ,case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 1 then dateadd(day,-1,@Date) else @Date end ) + 1end

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create function udf_WeekDay(@ int,@Date datetime)returns datetime-- 返回 @Date 映射到 所在周的其他天 周日是当周的最后一天begin/*--周日算作(上一)周的最后一天 当 @ <= 1 代表将 @Date 映射到 所在周的星期一 当 @ = 2 代表将 @Date 映射到 所在周的星期二 当 @ = 3 代表将 @Date 映射到 所在周的星期三 当 @ = 4 代表将 @Date 映射到 所在周的星期四 当 @ = 5 代表将 @Date 映射到 所在周的星期五 当 @ = 6 代表将 @Date 映射到 所在周的星期六 当 @ >= 7 代表将 @Date 映射到 所在周的星期日 可用于按周汇总 Group by,均支持跨年跨月数据*/return dateadd(day ,case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 0 --周六 then case when @ between 1 and 6 then @ - 6 else 1 end when (@@Datefirst + datepart(weekday,@Date)) % 7 = 1 --周日(七) then case when @ between 1 and 6 then @ - 7 else 0 end when (@@Datefirst + datepart(weekday,@Date)) % 7 between 2 and 6 --周一至周五 then case when @ between 1 and 6 then @ + 1 - (@@Datefirst + datepart(weekday,@Date)) % 7 else 8 - (@@Datefirst + datepart(weekday,@Date)) % 7 end end ,@Date)end

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create function udf_WeekdayDiff(@Weekday integer,@StartDate datetime,@EndDate datetime)returns integer-- -- 返回 [@StartDate , @EndDate] 之间周一 到 周日的个数 周日是当周的最后一天begin-- @Weekday: 1: Monday , ... ,7: Sundayreturn datediff(week,@StartDate,@EndDate) + case when (@@Datefirst + datepart(weekday,@StartDate)) % 7 + case when (@@Datefirst + datepart(weekday,@StartDate)) % 7 = 0 then 7 else 0 end > @Weekday % 7 + 1 then 0 else 1 end - case when (@@Datefirst + datepart(weekday,@EndDate)) % 7 + case when (@@Datefirst + datepart(weekday,@EndDate)) % 7 = 0 then 7 else 0 end >= @Weekday % 7 + 1 then 0 else 1 end/* test:

declare @b datetimedeclare @e datetime

set @b = \'2004-01-29\'set @e = \'2004-09-05\'

select @b as BeginDate ,@e as EndDate,dbo.udf_WeekdayDiff(1,@b,@e) as CountOfMonday,dbo.udf_WeekdayDiff(2,@b,@e) as CountOfTuesday,dbo.udf_WeekdayDiff(3,@b,@e) as CountOfWednesday,dbo.udf_WeekdayDiff(4,@b,@e) as CountOfThursday,dbo.udf_WeekdayDiff(5,@b,@e) as CountOfFriday,dbo.udf_WeekdayDiff(6,@b,@e) as CountOfSaturday,dbo.udf_WeekdayDiff(7,@b,@e) as CountOfSunday*/end

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create function udf_WeekdayID(@Date datetime)returns integer-- 返回 @Date 是 Monday 返回 1, ... ,是 Sunday 返回 1begin--1: Monday , ... ,7: Sundayreturn (@@Datefirst + datepart(weekday,@Date)) % 7 + case when (@@Datefirst + datepart(weekday,@Date)) % 7 < 2 then 6 else -1 endend

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create function udf_NextWorkDate(@Date datetime)returns datetime-- 返回 @Date 的下一个工作日begin/*declare @i intset @i = 3declare @Date datetimeset @Date = \'2005-01-02\'-- */return case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 6 -- Friday then dateadd(day,3,@Date) when (@@Datefirst + datepart(weekday,@Date)) % 7 = 0 -- saturday then dateadd(day,2,@Date) else dateadd(day,1,@Date) endend

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create function udf_PreviousWorkDate(@Date datetime)returns datetime-- 返回 @Date 的上一个工作日begin/*declare @i intset @i = 3declare @Date datetimeset @Date = \'2005-01-02\'-- */return case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 2 -- Monday then dateadd(day,-3,@Date) when (@@Datefirst + datepart(weekday,@Date)) % 7 = 1 -- Sunday then dateadd(day,-2,@Date) else dateadd(day,-1,@Date) endend

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create function udf_WorkDateAdd(@i integer,@Date datetime)returns datetime-- 返回 @Date 加上一段 @i 个工作日的新值begindeclare @ intset @ = 0while @ < abs(@i)begin set @Date = case when @i >= 0 then --dbo.udf_nextworkdate(@Date) case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 6 -- Friday then dateadd(day,3,@Date) when (@@Datefirst + datepart(weekday,@Date)) % 7 = 0 -- saturday then dateadd(day,2,@Date) else dateadd(day,1,@Date) end else --dbo.udf_previousworkdate(@Date) case when (@@Datefirst + datepart(weekday,@Date)) % 7 = 2 -- Monday then dateadd(day,-3,@Date) when (@@Datefirst + datepart(weekday,@Date)) % 7 = 1 -- Sunday then dateadd(day,-2,@Date) else dateadd(day,-1,@Date) end end set @ = @ + 1 endreturn @Dateend

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create function udf_GetStar (@ datetime)RETURNS varchar(100)-- 返回日期所属星座BEGINRETURN(--declare @ datetime--set @ = getdate()select max(star)from(select \'魔羯座\' as star,1 as [month],1 as [day]union all select \'水瓶座\',1,20union all select \'双鱼座\',2,19union all select \'牡羊座\',3,21union all select \'金牛座\',4,20union all select \'双子座\',5,21union all select \'巨蟹座\',6,22union all select \'狮子座\',7,23union all select \'处女座\',8,23union all select \'天秤座\',9,23union all select \'天蝎座\',10,24union all select \'射手座\',11,22union all select \'魔羯座\',12,22) starswhere dateadd(month,[month] - 1,dateadd(year,year(@) - year(0),0)) + [day] - 1 =(select max(dateadd(month,[month] - 1,dateadd(year,year(@) - year(0),0)) + [day] - 1)from (select \'魔羯座\' as star,1 as [month],1 as [day]union all select \'水瓶座\',1,20union all select \'双鱼座\',2,19union all select \'牡羊座\',3,21union all select \'金牛座\',4,20union all select \'双子座\',5,21union all select \'巨蟹座\',6,22union all select \'狮子座\',7,23union all select \'处女座\',8,23union all select \'天秤座\',9,23union all select \'天蝎座\',10,24union all select \'射手座\',11,22union all select \'魔羯座\',12,22) starswhere @ >= dateadd(month,[month] - 1,dateadd(year,year(@) - year(0),0)) + [day] - 1))end