How to Fix “Your PHP Installation Appears to Be Missing the MySQL Extension Which Is Required by WordPress” Error

If you are seeing this error message when trying to run WordPress, it means that the PHP installation on your server is missing the MySQL extension. This extension is required by WordPress in order to connect to and interact with a MySQL database.

To fix this problem, you will need to install the MySQL extension for PHP on your server. The exact steps for doing this will depend on your server's operating system and the version of PHP that you are using. Here are some general steps that you can follow:

Check which version of PHP you are using on your server. You can do this by running the php -v command in a terminal window.
Install the MySQL extension for PHP by running the appropriate command for your operating system. For example, on Ubuntu you can use the following command:

sudo apt-get install php-mysql

Restart your web server to apply the changes. For example, if you are using Apache, you can use the following command:

sudo service apache2 restart

Check that the MySQL extension for PHP is now installed by running the php -m command in a terminal window. This command should print a list of all installed PHP modules, and the MySQL extension should be included in this list.

Once you have installed the MySQL extension for PHP, you should be able to run WordPress without seeing the error message.