[Mediawiki-l] How to determine if string exists within any username in database

[Brian Carpenter]

What php code is needed to determine if "394433" exists at the end of any
username?

myphpadmin created the following sql:
SELECT * FROM `user`WHERE `user_name` LIKE CONVERT( _utf8 '%395523%'USING
latin1 )

but I can't find any meta article explaining how to make such a query and
return a boolean value:

This would be used to trigger a rename_user function.

Overview-
Our Single Sign-on process provides a unique username in the form of
firstname_lastname_ID (the ID never changes but the name could due to
marriage).
If this username exists within MediaWiki, the user is logged-in. If not, an
extension creates a new user. I need the above check(and rename_user
function) prior to creating a new user.

This is a tangent discussion to
"Best strategy to populate User data from Single Sign On?"
http://mail.wikipedia.org/pipermail/mediawiki-l/2006-April/011719.html
but may apply to a wider audience....

Thanks in advance for any response..
bc