How can users troubleshoot the "Call to undefined function: mysql_connect()" error in PHP when MySQL support seems to be missing?

The "Call to undefined function: mysql_connect()" error in PHP occurs when the MySQL extension is missing or not enabled. To solve this issue, users can switch to using the MySQLi or PDO extension, which are preferred over the deprecated MySQL extension. This can be done by modifying the PHP configuration file (php.ini) to enable the desired extension.

// Enable MySQLi extension
extension=mysqli

// Enable PDO extension
extension=pdo_mysql