[DuBois+ 99] DuBois, Paul, and Michael Widenius. MySQL. Covers MySQL for the newbie and the experienced user.
[Hatch+ 02] Hatch, Brian, James Lee, and George Kurtz. Hacking Linux Exposed: Linux Security Secrets and Solutions, Second Edition. Be sure to read the discussion on how to create good passwords.
[Yarger+ 99] Yarger, Randy Jay, George Reese, and Tim King. MySQL and mSQL. An excellent book that covers both MySQL and mSQL, two common databases on Linux systems.
MySQL home page: www.mysql.com/