Add business days to date in SQL without loops

Question

I currently have a function in my SQL database that adds a certain amount of business days to a date, e.g. if you enter a date that is a Thursday and add two days, it will r

Answer 1

Thanks Damien for the code. There was a slight error in the calcs in that it added only 1 day for the sunday, and that when the number of business days crossed a weekend (but did not land in the weekend) the extra 2 days was not taken into account. Here is a modified version of Damiens code that works with the default datefirst at 7. Hope this helps.

CREATE FUNCTION [dbo].[fn_AddBusinessDays]  
(  
    @StartDate datetime,  
    @BusinessDays int  
) 
RETURNS datetime  
AS  
BEGIN 
DECLARE @EndDate datetime

SET @EndDate = DATEADD(day, @BusinessDays%5 + 
           CASE         
        WHEN DATEPART(weekday,@StartDate) +  @BusinessDays%5 > 6 THEN 2                  
        ELSE 0 
           END,     
   DATEADD(week,@BusinessDays/5,@StartDate))    

   RETURN @EndDate
END  
GO