The primary MySQL web site is http://www.mysql.com/.
MySQL Administrator's Guide and Language Reference
MySQL AB. MySQL Press: 2006. ISBN: 0-672-32870-4
This is the printed form of the MySQL Reference Manual that is available online at the MySQL web site, http://dev.mysql.com/doc/.
MySQL
Paul DuBois. Sams Developers Library: 2005. ISBN: 0-672-32673-6
This book provides general information about MySQL use and administration. It also covers MySQL programming, with chapters on the C, Perl, and PHP APIs.