declare
@startdate date,
@enddate date
set @enddate='20120901'
set @startdate='20120316'
select @startdate ,@enddate
,DATEDIFF(YY,@startdate,@enddate)'int.age in years'
,DATEDIFF(DD,@startdate,@enddate )'int.age in days'
,DATEDIFF(mm,@startdate,@enddate)'int.age in months'