15 个与日期时间相关的自定义函数 - MYSQL

/*

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())

begin

return datediff(year,@StartDate,@EndDate)

- case when datediff(day,dateadd(year,datediff(year,@StartDate,@EndDate),@StartDate),@EndDate) >= 0

then 0

else

1

end

end

go

create function udf_DaysOfYearByDate(@Date datetime)

RETURNS integer

-- 返回年的天数可判断平(365)、润(366) 年

begin

return datediff(day,dateadd(year,datediff(year,0,@Date),0),dateadd(year,datediff(year,0,@Date )+1,0))

end

go

create function udf_DaysOfYear(@Year integer)

RETURNS integer

-- 返回年的天数可判断平(365)、润(366) 年

begin

return datediff(day,dateadd(year,@year - year(0),0),dateadd(year,@year - year(0) + 1,0))

end

go

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

as

begin

return 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

end

end

go

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

begin

return 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

end

end

go

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 integer

as

begin

return 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

) + 1

end

go

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 int

as

begin

return 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

) + 1

end

go

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 int

as

begin

return 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

) + 1

end

go

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 @ = 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

go

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: Sunday

return 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 datetime

declare @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

go

create function udf_WeekdayID(@Date datetime)

returns integer

-- 返回 @Date 是 Monday 返回 1, ... ,是 Sunday 返回 1

begin

--1: Monday , ... ,7: Sunday

return (@@Datefirst + datepart(weekday,@Date)) % 7

+ case when (@@Datefirst + datepart(weekday,@Date)) % 7 < 2

then 6

else

-1

end

end

go

create function udf_NextWorkDate(@Date datetime)

returns datetime

-- 返回 @Date 的下一个工作日

begin

/*

declare @i int

set @i = 3

declare @Date datetime

set @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)

end

end

go

create function udf_PreviousWorkDate(@Date datetime)

returns datetime

-- 返回 @Date 的上一个工作日

begin

/*

declare @i int

set @i = 3

declare @Date datetime

set @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)

end

end

go

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

begin

declare @ int

set @ = 0

while @ < 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

end

return @Date

end

go

create function udf_GetStar (@ datetime)

RETURNS varchar(100)

-- 返回日期所属星座

BEGIN

RETURN

(

--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',1,20

union all select '双鱼座',2,19

union all select '牡羊座',3,21

union all select '金牛座',4,20

union all select '双子座',5,21

union all select '巨蟹座',6,22

union all select '狮子座',7,23

union all select '处女座',8,23

union all select '天秤座',9,23

union all select '天蝎座',10,24

union all select '射手座',11,22

union all select '魔羯座',12,22

) stars

where 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',1,20

union all select '双鱼座',2,19

union all select '牡羊座',3,21

union all select '金牛座',4,20

union all select '双子座',5,21

union all select '巨蟹座',6,22

union all select '狮子座',7,23

union all select '处女座',8,23

union all select '天秤座',9,23

union all select '天蝎座',10,24

union all select '射手座',11,22

union all select '魔羯座',12,22

) stars

where @ >= dateadd(month,[month] - 1,dateadd(year,year(@) - year(0),0)) + [day] - 1

)

)

end