Finding users to shred

Hi Folks,
Does anyone have a query or a script that can find users
in the database who aren’t referenced by any tickets?
I’d like to find users who were created by spam who
are now candidates for shredding.
-Chuck Boeheim

There is an example for this in rt-wiki.:
rt-shredder --plugin "Users=no_tickets,1;status,any;replace_relations,Nobody;limit,5" --sqldump /{somepath}/shredder-restore-users.sql --force