How to upgrade cPanel MySQL 5.1 to 5.5
Updating from MySQL 5.0 to 5.5
If you are running your server on MySQL 5.0. then most probably there is a requirement to update your mysql 5.0 to mysql 5.5 version. And the best way to update your mysql from version 5.0 to mysql 5.5 is via Web Host Manager as there are chances and high risk of breaking something from this upgrade.
Still if you wants to update the Mysql version by yourself then.. go through the given tutorial that provides you a step by step process to update the mysql version. upgrading from 5.1 to 5.5
Here is the cPanel Updating from MySQL 5.0 to 5.5