Calculate Number of Working Days in SQL Server , FirstDayOfQuarter and LastDayOfQuarter

--FirstDayOfQuarter
SELECT DATEADD(qq,DATEDIFF(qq,0,GETDATE()),0) as FirstDayOfQuarter

--LastDayOfQuarter
SELECT DATEADD(qq,DATEDIFF(qq,-1,GETDATE()),-1) as LastDayOfQuarter

--Calculate Number of Working Days in SQL Server
DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME
SET @StartDate = '2009/1/01'
SET @EndDate = GETDATE()
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)