Michael Widenius, David Axmark and MySQL AB MySQL Reference Manual O'Reilly & Associates.
Paul DuBois. MySQL. New Riders.
A FAQ for MySQL is available at http://www.bitbybit.dk/mysqlfaq/. This site also provides a useful index of changes and updates to MySQL, which is helpful for determining whether a feature you're trying to use is present in your version.
Using the mysql Client Program
Writing MySQL-Based Programs
Record Selection Techniques
Working with Strings
Working with Dates and Times
Sorting Query Results
Modifying Tables with ALTER TABLE
Obtaining and Using Metadata
Importing and Exporting Data
Generating and Using Sequences
Using Multiple Tables
Introduction to MySQL on the Web
Incorporating Query Resultsinto Web Pages
Processing Web Input with MySQL
Using MySQL-Based Web Session Management
Appendix A. Obtaining MySQL Software
Appendix B. JSP and Tomcat Primer
Appendix C. References