A colleague of mine just sent me this hugely useful MySQL command for seeing which users have privileges in a database, and from which host. It prints a list of other MySQL commands which can then be used to show more precisely what privileges that user has been granted.
SELECT DISTINCT CONCAT('SHOW GRANTS FOR ''',user,'''@''',host,''';') AS query FROM mysql.user;
Prior to this, I found myself having to connect to the database from the appropriate (remote) MySQL client and issue a
SHOW GRANTS from there.
Thanks to Mate Racz for this one.