I have had a forum member change their username, which was approved by admin. However, the problem I see is that he is still referred in posts by the old name. Is there an sql query I can run to change any reference from old to new?

Thanks!

you mean in the actual post bodies ?

so someone is saying "hi there, oldname"

and you want all occurrences of that names changed ?

That's exactly what I mean.

Thanks!

Well, referances to them in posts are type in by users; this is not something you could easily fix without a lot of content rebuilding and database diving and would be completley unrecomended.