These functions allow you to access MySQL database servers. In order to have these functions available, you must compile PHP with MySQL support by using the --with-mysql option. If you use this option without specifying the path to MySQL, PHP will use the built-in MySQL client libraries. Users who run other applications that use MySQL (for example, running PHP 3 and PHP 4 as concurrent apache modules, or auth-mysql) should always specify the path to MySQL: --with-mysql=/path/to/mysql. This will force PHP to use the client libraries installed by MySQL, avoiding any conflicts.
More information about MySQL can be found at http://www.mysql.com/.
Documentation for MySQL can be found at http://www.mysql.com/documentation/.
This simple example shows how to connect, execute a query, print resulting rows and disconnect from a MySQL database.
Example 1. MySQL extension overview example