Count work days between two dates

Question

How can I calculate the number of workdays between two dates in SQL Server?

Monday to Friday and it must be T-SQL.

Answer 1

Monday to Friday, for workdays you can do it with a single SELECT, this way:

DECLARE @StartDate DATETIME

DECLARE @EndDate DATETIME

SET @StartDate = '2008/10/01'

SET @EndDate = '2008/10/31'

SELECT

   (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)