Have a look at my post here (3rd post down): DB-specific Relative Dates SQL Server, Oracle, Netezza, DB2
There are some relative dates that work in multisource IDT. You may be able to pick something out from that?
These were based on code I found at http://www.smallsql.de/doc/sql-functions/date-time/index.html - and a lot of time, effort, coffee and swearing…
Debbie
Debbie 
(BOB member since 2005-03-01)