We’ve updated the Small Business platform to support MySQL 5. If you’re using a database with your site or store, we recommend that you upgrade now to take advantage of better performance and enhanced features.
Yahoo finally updated their Small Buisness platform to support MySQL 5. Upgrading is really, and here is how:


Sometimes, you will receive a error message saying you should repair your database. Ignore this message and installing your database again.
Official guide: http://help.yahoo.com/l/us/yahoo/smallbusiness/webhosting/mysql/mysql-26.html