I recently bumped into this handy query from CMS which shows how to calculate the number of working days in this year till now. The working days are assumed to be Monday to Friday and does not include public holidays, which may be added by you later depending on the country you live in.
DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME
SET @StartDate = '2009/1/01'
SET @EndDate = GETDATE()
(DATEDIFF(dd, @StartDate, @EndDate) + 1)
-(DATEDIFF(wk, @StartDate, @EndDate) * 2)
-(CASE WHEN DATENAME(dw, @StartDate) = 'Sunday' THEN 1 ELSE 0 END)
-(CASE WHEN DATENAME(dw, @EndDate) = 'Saturday' THEN 1 ELSE 0 END)
Assuming the current date is 'May 20, 2009', the number of working days after this query is 100
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Suprotim Agarwal, ASP.NET Architecture MVP works as an Architect Consultant and provides consultancy on how to design and develop Web applications.