To remove an instance of MySQL from your macOS or OSX installation you need to delete a number of files via the command line, but first ensure that you have database dumps of your databases and that then the database server is not running.
Back Up any needed databases
All of them
mysqldump --all-databases > all_databases_export.sql
Or individually
mysqldump database_name > database_exportname.sql
Stop the database server
>= MySQL 5.7
sudo launchctl unload -F /Library/LaunchDaemons/com.oracle.oss.mysql.mysqld.plist
< MySQL 5.7
sudo /usr/local/mysql/support-files/mysql.server stop
Remove MySQL
sudo rm -rf /usr/local/mysq*
sudo rm /Library/LaunchDaemons/com.oracle.oss.mysql.mysqld.plist
sudo rm -rf /Library/StartupItems/MySQLCOM
sudo rm -rf /Library/PreferencePanes/My*
Edit /etc/hostconfig and remove the line MYSQLCOM=
rm -rf ~/Library/PreferencePanes/MySQL*
sudo rm -rf /Library/Receipts/mysql*
sudo rm -rf /Library/Receipts/MySQL*
sudo rm -rf /private/var/db/receipts/*mysql*
That’s it MySQL is now totally removed from your system