SQL Server :calcul des plages de dates

SELECT  'Anything' as Label
        ,DATEADD(month, DATEDIFF(month, 0, GETDATE()), 0) as firstdaythismonth
        ,DATEADD(day, DATEDIFF(day, 0, GETDATE()), 0) as today
        ,DATEADD(year, -1, DATEADD(month, DATEDIFF(month, 0, GETDATE()), 0)) as firstdaythismonth_lastyear
        ,DATEADD(year, -1, DATEADD(day, DATEDIFF(day, 0, GETDATE()), 0)) as today_lastyear