How do I match a client ID with a user without digging around in the DB

I'm trying to use the client IDs (Read: NOT THE UID) as seen in the server log to determine what users were added to what server groups by who but the ID (Which is a number) isn't useful for this purpose and doesn't correlate with the UID or the username of the users in question.

From what I've read I have to go digging around querying in the database to make any use of the admin log? Seems like very poor design as I'm not giving all my moderators query access. Is there a better way?

How do I match a client ID with a user without digging around in the DB