1. Execute the following commands in terminal

   	sudo rm /usr/local/mysql
   	sudo rm -rf /usr/local/mysql*
   	sudo rm -rf /Library/StartupItems/MySQLCOM
   	sudo rm -rf /Library/PreferencePanes/My*
   	sudo rm -rf /Library/Receipts/mysql*
   	sudo rm -rf /Library/Receipts/MySQL*

   view raw uninstall_mysql.sh hosted with ❤ by GitHub
2. Update hostConfig
   • Open /etc/hostconfig
   • Remove the line MYSQLCOM=-YES-

Credits