[Zope] Substracting value from variable?

1 Aug 2000

      Hi all,

Is there a way to have a ZSQL Method select the four highest values 
from a list of values in a database? Example:

  select distinct year from table

returns the following results

  1975
  1980
  1985
  1990
  1995
  2000

from which I want to select the latest four years:

  1985
  1990
  1995
  2000

Possible? Can't seem to find anything in the docs :(

Thnx,
Jonathan