Uninstalling MySQL Community Server on OS X Revision as of Friday, 4 June 2021 at 03:52 UTC

Tested on 10.7 (Lion) and 10.6 (Snow Leopard).

Remove all startup items, receipts and the MySQL installation directory:

sudo rm -rf /Library/StartupItems/MySQL*  
sudo rm -rf /Library/PreferencePanes/MySQL*  
sudo rm -rf /Library/Receipts/mysql-*  
sudo rm -rf /var/db/receipts/com.mysql.*  
sudo rm /usr/local/mysql  
sudo rm -rf /usr/local/mysql-*

Remove this in /etc/hostconfig

MYSQLCOM=-NO-

Done.