You can check the MySQL version using the phpinfo function. To do this, you should create a simple php file (for example phpinfo.php) with the following line in it:

<?php phpinfo(); ?>

Then you should open this file in a browser to see the full Apache/PHP information. The path to the file should be:

yourdomainname.com/phpinfo.php

The MySQL version is shown next to Client API version in the MySQL section of the file.