Consider my limited experience with this, and here's the "idea" of what I want to do:
DELETE FROM `users` INNER JOIN `users_roles` ON `users.uid` = `users_roles.uid` WHERE `users_roles.rid` (7, 5, 6);
I don't think that's right, because I get a syntax error, and this is nothing I want to be unsure about, of course.
* MySQL client version: 5.1.41
* Drupal 6.19