The Closest Date

Is there any way in SQL of selecting a date closest to another date.

i.e. I have a date say 4/4/2002, and in the database I have dates 4/2/2002 and earlier and 4/7/2002 and later.

I want to do a query and return the date 4/2/2002 as it is only 2 days away even though it is an earlier date.

So short of writing a loop and saying if the date is eq then good else, take date and add a day if not correct take initial date and subtract a day etc etc. This way is proving to be a little too processor heavy.

Thanks