Martin, Even if there's no technical reason involving the Oracle optimizer, it just makes sense to write code that's easily maintainable and understandable. I would consider mixing the syntax like that to be confusing to someone else reading it in the future, and that's enough reason for me to avoid it. Also, please consider a recent blog post by Jonathan Lewis: http://jonathanlewis.wordpress.com/2010/12/15/join-surprise/ I think it's likely that mixing the two would cause some problem in the CBO, and although I can't find a case yet to prove it, I wouldn't mix them. Ron Crisco On Wed, Dec 22, 2010 at 1:27 AM, Martin Berger <martin.a.berger@xxxxxxxxx>wrote: > Hi List, > > somewhere in the back of my brain I have the ruleset 'do not mix ANSI and > Oracle JOINs within the same SQL'. > As I have no reference for this I'd like to crosscheck such memories from > time to time as a) this memory is quite unstable and b) as Oracle changes, > it should be checked from time to time. > I searched MOS and asked google, but did not find a real reason. > Should I wipe this memory? > > Martin-- > //www.freelists.org/webpage/oracle-l > > >