LISTING 1: Code That Uses DATEDIFF() to 
Determine Whether You’ve Crossed a Datetime Boundary

DECLARE @InputDate datetime
SET @InputDate =  '2001-11-29' --getdate()
SELECT DATEDIFF ( mm , @InputDate, @InputDate + 1 )
GO

DECLARE @InputDate datetime
SET @InputDate =  '2001-11-30' --getdate()
SELECT DATEDIFF ( mm , @InputDate, @InputDate + 1 )