Folgende Beschreibung hab ich im entwickler-forum.de gefunden.
Über die DATEPART-Funktion kann eine SELECT-Abfrage nur bestimmte Bestandteile zurückliefern.
DECLARE @mydatetime DATETIME
DECLARE @myms INT
DECLARE @myss INT
DECLARE @mymi INT
DECLARE @myhh INT
DECLARE @mydd INT
DECLARE @mymm INT
DECLARE @myyyyy INT
SET @mydatetime=getdate()
SET @myms = DATEPART(ms,@mydatetime)
SET @myss = DATEPART(ss,@mydatetime)
SET @mymi = DATEPART(mi,@mydatetime)
SET @myhh = DATEPART(hh,@mydatetime)
SET @mydd = DATEPART(dd, @mydatetime)
SET @mymm=DATEPART(mm,@mydatetime)
SET @myyyyy = DATEPART(yyyy, @mydatetime)
SELECT @myyyyy AS 'Year', @mymm AS 'Month', @mydd AS 'Day of month',
@myhh AS 'Hour', @mymi AS 'Minute', @myss AS 'Second',
@myms AS 'Millisecond'