Calculate business hours between two dates

Question

How can I calculate business hours between two dates? For example we have two dates; 01/01/2010 15:00 and 04/01/2010 12:00 And we have working hours 09:00 to 17:00 in weekda

Answer 1

DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME
DECLARE @WORKINGHOURS INT
DECLARE @Days INT
SET @StartDate = '2010/01/01'
SET @EndDate = '2010/04/01'

--number of working days
SELECT @Days = 
   (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)

--8 hours a day    
SET @WORKINGHOURS = @Days * 8 

SELECT @WORKINGHOURS