&reftitle.install; By using the --with-mysql[=DIR] configuration option you enable PHP to access MySQL databases. In PHP 4, the option --with-mysql is enabled by default. To disable this default behavior, you may use the --without-mysql configure option. Also in PHP 4, if you enable MySQL without specifying the path to the MySQL install DIR, PHP will use the bundled MySQL client libraries. In Windows, there is no DLL, it's simply built into PHP 4. Users who run other applications that use MySQL (for example, auth-mysql) should not use the bundled library, but rather specify the path to MySQL's install directory, like so: --with-mysql=/path/to/mysql. This will force PHP to use the client libraries installed by MySQL, thus avoiding any conflicts. In PHP 5, MySQL is no longer enabled by default, nor is the MySQL library bundled with PHP. Read this FAQ for details on why. Windows users will need to enable php_mysql.dll inside of &php.ini; and either copy libmysql.dll into the Windows system directory, or make it available to the PATH. This will fix "Unable to load dynamic library './php_mysql.dll'" errors. For compiling, simply use --with-mysql=[DIR] where [DIR] points to your MySQL installation directory. This MySQL extension doesn't support full functionality of MySQL versions greater than 4.1.0. For that, use MySQLi. If you would like to install the mysql extension along with the mysqli extension you have to use the same client library to avoid any conflicts. Crashes and startup problems of PHP may be encountered when loading this extension in conjunction with the recode extension. See the recode extension for more information. If you need charsets other than latin (default), you have to install external (not bundled) libmysql with compiled charset support.