How to get Previous business day in a week with that of current Business Day using sql server

Question

i have an ssis Package which runs on business days (mon-Fri). if i receive file on tuesday , background(DB), it takes previous business day date and does some transactions.

Answer 1

thanks for the tips above, I had a slight variant on the query in that my user needed all values for the previous business date. For example, today is a Monday so he needs everything between last Friday at midnight through to Saturday at Midnight. I did this using a combo of the above, and "between", just if anyone is interested. I'm not a massive techie.

-- Declare a variable for the start and end dates.
declare @StartDate as datetime 
declare @EndDate as datetime 

SELECT  @StartDate = DATEADD(DAY, CASE DATENAME(WEEKDAY, GETDATE()) 
WHEN 'Sunday' THEN -2 
WHEN 'Monday' THEN -3 
    ELSE -1 END, DATEDIFF(DAY, 0, GETDATE()))
select @EndDate = @StartDate + 1 
select @StartDate , @EndDate 
-- Later on in the query use "between"
and mydate between @StartDate and @EndDate

Answer 2

select  
  dateadd(dd, 
             case DATEPART(dw, getdate()) 
             when 1 
             then -2 
             when 2 
             then -3 
             else -1 
         end, GETDATE())

Answer 3

This function returns last working day and takes into account holidays and weekends. You will need to create a simple holiday table.

-- =============================================
-- Author:      Dale Kilian
-- Create date: 2019-04-29
-- Description: recursive function returns last work day for weekends and 
-- holidays
-- =============================================
ALTER FUNCTION dbo.fnGetWorkWeekday
(
    @theDate DATE
)
RETURNS DATE
AS
BEGIN

DECLARE @importDate DATE = @theDate
DECLARE @returnDate DATE
--Holidays
IF EXISTS(SELECT 1 FROM dbo.Holidays WHERE isDeleted = 0 AND @theDate = Holiday_Date)
BEGIN
SET @importDate = DATEADD(DAY,-1,@theDate);
SET @importDate = (SELECT dbo.fnGetWorkWeekday(@importDate))
END
--Satruday
IF(DATEPART(WEEKDAY,@theDate) = 7)
BEGIN
    SET @importDate = DATEADD(DAY,-1,@theDate);
    SET @importDate = (SELECT dbo.fnGetWorkWeekday(@importDate))
END
--Sunday
IF(DATEPART(WEEKDAY,@theDate) = 1)
BEGIN
    SET @importDate = DATEADD(DAY,-2,@theDate);
    SET @importDate = (SELECT dbo.fnGetWorkWeekday(@importDate))
END


RETURN @importDate;
END
GO

Answer 4

Then how about:

declare @dt datetime='1 dec 2012'

select case when 8-@@DATEFIRST=DATEPART(dw,@dt)  
            then DATEADD(d,-2,@dt)  
        when (9-@@DATEFIRST)%7=DATEPART(dw,@dt)%7  
            then DATEADD(d,-3,@dt)  
        else DATEADD(d,-1,@dt)  
    end

Answer 5

More elegant:

select DATEADD(DAY, 
CASE when datepart (dw,Getdate()) < 3 then datepart (dw,Getdate()) * -1 + -1 ELSE -1 END,
cast(GETDATE() as date))

Answer 6

The simplest solution to find the previous business day is to use a calendar table with a column called IsBusinessDay or something similar. The your query is something like this:

select max(BaseDate)
from dbo.Calendar c
where c.IsBusinessDay = 0x1 and c.BaseDate < @InputDate

The problem with using functions is that when (not if) you have to create exceptions for any reason (national holidays etc.) the code quickly becomes unmaintainable; with the table, you just UPDATE a single value. A table also makes it much easier to answer questions like "how many business days are there between dates X and Y", which are quite common in reporting tasks.