sql-server - 用一个月的最后三天检查当前日期

Question

我想检查当前日期是否等于一个月的最后三天，不包括周六和周日......

我可以得到一个月的最后一天

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

我不知道如何检查getdate()每月的最后三天，不包括周六和周日..

会有很大帮助..谢谢

Answer 1

-- make sure Sunday is the first day of the week:
SET DATEFIRST 7;

DECLARE 
  @today SMALLDATETIME,
  @nextmonth SMALLDATETIME;

-- today at midnight is the number of days since 1900-01-01
-- the first day of nextmonth is one month after the first 
-- day of the current month 
SELECT 
  @today = DATEDIFF(DAY, '19000101', CURRENT_TIMESTAMP),
  @nextmonth = DATEADD(MONTH, 1, @today-DAY(@today)+1);

-- so if today is greater than 3 days prior to the first of next month
-- and today is not a Saturday or a Sunday:
IF @today >= DATEADD(DAY, -3, @nextmonth) 
  AND DATEPART(WEEKDAY, @today) NOT IN (1,7)
BEGIN
  PRINT 'Bazinga!';
END

如果您的真正意思是您想要该月的最后三个非周末，那么：

SET DATEFIRST 7;

DECLARE 
  @today SMALLDATETIME,
  @nextmonth SMALLDATETIME;

SELECT 
  @today = DATEDIFF(DAY, 0, GETDATE()),
  @nextmonth = DATEADD(MONTH, 1, @today-DAY(@today)+1);

;WITH x AS
(
  -- get the 5 days prior to the first day of next month:
  SELECT TOP (5) d = DATEADD(DAY, -ROW_NUMBER() OVER 
   (ORDER BY [object_id]), @nextmonth) FROM sys.all_objects
), 
y AS
(
  -- get the last three days that aren't on Sat/Sun:
  SELECT TOP (3) d FROM x 
  WHERE DATEPART(WEEKDAY, d) NOT IN (1,7)
  ORDER BY d DESC
)
-- now find out if today is in those three days:
-- (by definition, today can't be Sat/Sun)
SELECT 'Bazinga!' FROM y WHERE d = @today;

如果今天不在这三天内，这将不会产生任何结果。

Answer 2

这也给出了一个月的最后三天，不包括周六和周日

选择 LastFriDay,LastFriDay-1 LastThursday,LastFriDay-2 LastWednesday FROM ( SELECT DATEADD(mm,1,GETDATE() - DAY(GETDATE())+1)-1 AS LastFriDay UNION ALL SELECT DATEADD(mm,1,GETDATE() - DAY(GETDATE())+1)-2 AS LastFriDay UNION ALL SELECT DATEADD(mm,1,GETDATE() - DAY(GETDATE())+1)-3 AS LastFriDay UNION ALL SELECT DATEADD(mm,1,GETDATE () - DAY(GETDATE())+1)-4 AS LastFriDay UNION ALL SELECT DATEADD(mm,1,GETDATE() - DAY(GETDATE())+1)-5 AS LastFriDay UNION ALL SELECT DATEADD(mm,1 ,GETDATE() - DAY(GETDATE())+1)-6 AS LastFriDay UNION ALL SELECT DATEADD(mm,1,GETDATE() - DAY(GETDATE())+1)-7 AS LastFriDay ) AS YourFridayTable WHERE DATENAME( WeekDay,LastFriDay) = '星期五'