Uninstalling MySQL from macOS.

If you installed MySQL from an official package installer and you want to now uninstall it, just run the following commands. These commands assume the version of MySQL that was installed was mysql-5.5.12-osx10.6-x86_64 so adjust accordingly to match your setup:

First, go into /usr/local/:

cd /usr/local/

And get rid of the core MySQL stuff like this:

sudo rm mysql    
sudo rm -rf mysql-5.5.12-osx10.6-x86_64

Next, go into /Library/StartupItems/:

cd /Library/StartupItems/

And get rid of the MySQLCOM startup item like this:

sudo rm -rf MySQLCOM

Then, go into /Library/PreferencePanes/:

cd /Library/PreferencePanes/

And get rid of the MySQL.prefPane preference pane like this:

sudo rm -rf MySQL.prefPane

Finally, head into /Library/Receipts/:

cd /Library/Receipts/

And get rid of all MySQL related installation receipts like this:

sudo rm -rf mysql*    
sudo rm -rf MySQL*

Similarly, head into /var/db/receipts/:

cd /var/db/receipts/

And get rid of all MySQL related installation receipts like this:

sudo rm com.mysql.mysql.bom
sudo rm com.mysql.mysql.plist
sudo rm com.mysql.mysqlstartup.bom
sudo rm com.mysql.mysqlstartup.plist

Now edit /etc/hostconfig:

sudo nano /etc/hostconfig

And remove the line MySQL related line that should look like this:

MYSQLCOM=-YES-