Your PHP installation appears to be missing the MySQL extension which is required by WordPress on Ub-CodePudding

I am attempting to create a staging WordPress site where the PHP and WordPress versions are very outdated. When I visit localhost, I get the following error:

Your PHP installation appears to be missing the MySQL extension which is required by WordPress.

Ubuntu version: 20.04.2 LTS

PHP version CLI: PHP 7.2.34-24 ubuntu20.04.1 deb.sury.org 1

MySQL version: 8.0.26-0ubuntu0.20.04.3 for Linux on x86_64 ((Ubuntu))

WordPress version: 5.3.9

I need the PHP version to be 7.2.34 and the WordPress version to be 5.3.9.

In my info.php file, the Loaded Configuration path and extension_dir path are as follows:

Loaded Configuration File /etc/php/7.2/apache2/php.ini

extension_dir /usr/lib/php/20170718

Do these need to be the same?

Here is the Client API Library version. I'm a bit confused as to why this error is being thrown, doesn't this mean the extension is installed? I'm aware that in newer MySQL versions it was removed, but I am at a loss as to how to proceed.

Client API library version mysqlnd 5.0.12-dev - 20150407 - $Id: 3591daad22de08524295e1bd073aceeff11e6579 $

I have searched through the similar questions that have been posted, but none of the answers were helpful to this situation. Please let me know if I need to provide more information. Thank you.

CodePudding user response：

To check which extensions are installed, you can run this from the command line:


php -m

Or you can run this PHP script:

<?php
var_dump(get_loaded_extensions());

Look for 'mysql' in the results. Or you can grep for it from CLI:

php -m | grep -i 'mysql'

If you don't see any mysql module installed, that would suggest you have installed PHP in a pretty unusual fashion. For Ubuntu, you might need to install the mysql module like so:

# let APT decide which version
sudo apt install php-mysql
# or install a more specific version depending on which php you have:
sudo apt install php7.2-mysql

It's not clear if you have your system configured with PHP running as apache module or via PHP-FPM. If it's the latter, you'll need to restart php-fpm. I'd restart apache just for good measure:

sudo systemctl restart apache2

Also, that looks like a pretty old version of the client. Maybe check phpinfo() and see what information it has about mysql.

EDIT: some additional information.

I believe the wordpress function that is causing your error is wp_check_php_mysql_versions().

As you can see, that error could be caused by a number of conditions:

if ( ! extension_loaded( 'mysql' ) && ! extension_loaded( 'mysqli' ) && ! extension_loaded( 'mysqlnd' )
        // This runs before default constants are defined, so we can't assume WP_CONTENT_DIR is set yet.
        && ( defined( 'WP_CONTENT_DIR' ) && ! file_exists( WP_CONTENT_DIR . '/db.php' )
            || ! file_exists( ABSPATH . 'wp-content/db.php' ) )
    ) {
        require_once ABSPATH . WPINC . '/functions.php';
        wp_load_translations_early();
        $args = array(
            'exit' => false,
            'code' => 'mysql_not_found',
        );
        wp_die(
            __( 'Your PHP installation appears to be missing the MySQL extension which is required by WordPress.' ),
            __( 'Requirements Not Met' ),
            $args
        );
        exit( 1 );
    }

Try running this php script and it should tell you if the problem is lack of suitable extension or a missing file problem:

if (!extension_loaded('mysql')
  && !extension_loaded('mysqli')
  && !extension_loaded('mysqlnd')) {

  die("You lack any suitable mysql extensions\n");
} else {

  die("perhaps you are missing a file db.php?\n");
}

CodePudding user response：

You've got to make sure that the current version of MySQL and the corresponding version of the PHP extension are both installed and available.

PHP has necessarily become a modular system: various built-in functions are implemented by a particular module. (And are only "built in" if such a module is installed.)