help me to improve sql, plz

could you help me to improve sql

select
...

from ir, gw, ...
where
...

  and (ir.figw_src in (select figw_id from gw) or ir.figw_src is null)   and ir.figw_src = gw.figw_id (+) Received on Wed Feb 20 2002 - 08:41:09 CST