T-SQL 自动取件日期

Question

我正在寻找一些 T-SQL 代码，它应该选择“一月的最后一个星期日”这一日期。

例如：让我们假设，

情景 1： 当前日期为 - '2017-01-29'

• 代码应该选择 - '2016-01-31'

情景 2： 当前日期为 - '2017-02-05'

• 代码应该选择 - '2017-01-29'

情景 3： 当前日期为 - '2017-02-19'

• 代码应该选择 - '2017-01-29'

情景 4： 当前日期为 - '2018-01-28'

• 代码应该选择 - '2017-01-29'

Senario 5：当前日期是 - '2018-02-04'

• 代码应该选择 - '2018-01-28'

请注意：这是因为年份从一月的最后一个星期日开始

我有以下一些 T-SQL 代码，这些代码在 SQL Server 2014 中使用。它总是选择每年 1 月 31 日 - 这是错误的。

select CASE 
    WHEN    GETDATE() <= DATEADD(Day,-0,CONVERT(datetime, CONVERT(varchar(4), (year(GETDATE()))) + '-02-01'))
    THEN    DATEADD(Day,-1,CONVERT(datetime, CONVERT(varchar(4), (year(GETDATE())-1)) + '-02-01'))
    ELSE    DATEADD(Day,-1,CONVERT(datetime, CONVERT(varchar(4), (year(GETDATE()))) + '-02-01'))
END 

为什么总是选择 1 月 31 日？

Answer 1

您可以使用以下 SQL 查询来获取给定日期的最后日期

DECLARE @dtDate DATETIME
SET @dtDate = '2/21/2017'

SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,@dtDate)+1,0))

输出：2017-02-28 23:59:59.000

SELECT FORMAT(DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,@dtDate)+1,0)), 'yyyy-MM-dd') AS LastDate

输出：2017-02-28

Answer 2

DECLARE @LastJanuarySunday DATE = CONVERT(DATE,CAST((SELECT DATEPART(YEAR, GETDATE())) AS VARCHAR(4)) + '-01-01')
DECLARE @LastDay DATE = 
(SELECT DATEADD(dd,-(DATEPART(WEEKday, DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,convert(datetime,@LastJanuarySunday,112))+1,0)))-1),DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,convert(datetime,@LastJanuarySunday,112))+1,0))))
DECLARE @InputDate DATE = GETDATE()


SELECT CASE WHEN @InputDate > @LastDay AND @LastJanuarySunday <> @LastDay
   THEN @LastDay
   WHEN @InputDate = @LastDay
   THEN DATEADD(DAY, 2, @LastDay)
   END

这对你很有用。

Answer 3

最右边的列将计算任何日期在一月份的最后一个星期日。我将其他列作为一种简单的方式来记录和试验逻辑。

没有分支逻辑，它都是纯日期数学，因此它应该能够相当快地聚合，并且应该能够在日期列上使用索引。

DECLARE @Date DATE = '20170205';
SELECT SampleDate= @Date  ,
    EndOfSampleMonth = EOMONTH(@Date) ,
    SampleMonthNumber = DATEPART(MONTH,@Date) ,
    MostRecentJanuaryForSampleMonth = DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date) ,
    LastDayOfMostRecentJanuary = EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)) ,
    WeekDayOfLastDayOfMostRecentJanuary = DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date))) ,
    LastSundayOfJanuary = DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date))) ,
    LastSundayOfJanuaryDayOfYear= DATEPART(DAYOFYEAR,DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))) ,
    PushSampleDateToFiscalYear = DATEADD(DAY,(DATEPART(DAYOFYEAR,DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date))))) * -1 ,@date) ,
    PreviousLastSundayInJanuaryForSampleDate = DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH
,DATEADD(DAY,((DATEPART(DAYOFYEAR,DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))))-1) * -1 ,@Date))-1)*-1
,DATEADD(DAY,((DATEPART(DAYOFYEAR,DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))))-1) * -1 ,@Date))))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH
,DATEADD(DAY,((DATEPART(DAYOFYEAR,DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))))-1) * -1 ,@Date))-1)*-1
,DATEADD(DAY,((DATEPART(DAYOFYEAR,DATEADD(DAY,(DATEPART(WEEKDAY,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))-1)*-1,EOMONTH(DATEADD(MONTH,(DATEPART(MONTH,@Date)-1)*-1,@Date)))))-1) * -1 ,@Date)))) 

如果您尝试按会计年度分组，请将 PushSampleDatetoFiscalYear 包装在 YEAR() 函数中以输出日期所属的会计年度。要将其用于表格，请将 @Date 替换为您自己的日期字段。

更新了样本结果：

SampleDate  PreviousLastSundayInJanuaryForSampleDate
2008-06-03  2008-01-27
2008-12-20  2008-01-27
2009-07-08  2009-01-25
2010-01-24  2009-01-25
2010-08-12  2010-01-31
2011-02-28  2011-01-30
2011-09-16  2011-01-30
2012-04-03  2012-01-29
2012-10-20  2012-01-29
2013-05-08  2013-01-27
2013-11-24  2013-01-27
2014-06-12  2014-01-26
2014-12-29  2014-01-26
2015-07-17  2015-01-25
2016-02-02  2016-01-31
2016-08-20  2016-01-31
2017-03-08  2017-01-29
2017-09-24  2017-01-29
2018-04-12  2018-01-28
2018-10-29  2018-01-28
2019-05-17  2019-01-27
2019-12-03  2019-01-27
2020-06-20  2020-01-26

Answer 4

以下 T-SQL 为您提供所需的结果。

Declare @dtMyDate datetime

select @dtMyDate = '2017-01-25'

select case 
        when datepart(month,@dtMyDate) = 1

        then convert(varchar(10), DATEADD(day,DATEDIFF(day,'19000107',
        DATEADD(month,DATEDIFF(MONTH,0, 
        CONVERT(date, CONVERT(VARCHAR(4), dateadd(year,-1,@dtMyDate), 112)+'0101')),30))/7*7,'19000107'), 120)

        else convert(varchar(10), DATEADD(day,DATEDIFF(day,'19000107',
        DATEADD(month,DATEDIFF(MONTH,0, 
        CONVERT(date, CONVERT(VARCHAR(4), @dtMyDate, 112)+'0101')),30))/7*7,'19000107'), 120)
        end

结果：-

2016-01-31

对我有帮助的参考资料：-

how to extract current year and combine with specific month and date as a date

Find Last Sunday