uninstall mysql ubuntu 18.04
$ sudo apt-get remove –purge mysql-server mysql-client mysql-common -y
$ sudo apt-get autoremove -y
$ sudo apt-get autoclean
$ sudo rm -rf /etc/mysql
# Delete all MySQL files on your server:
$ sudo find / -iname ‘mysql*’ -exec rm -rf {} \;
mysql remove ubuntu
apt-get –purge remove “mysql*”
source : https://www.codegrepper.com/code-examples/sql/remove+mysql+from+ubuntu+18.04+completely