How to completely uninstall mysql in ubuntu

sudo dpkg --remove mysql-server
sudo  apt-get purge -f mysql-server mysql-common
sudo apt-get install mysql-server mysql-common 

after that,

sudo rm /var/lib/mysql/ -R
sudo rm /etc/mysql/ -R
sudo apt-get autoremove mysql* --purge
sudo apt-get remove apparmor

sudo dpkg --remove mysql-server
sudo  apt-get p