I need to completely remove MySQL all databases and installation and reinstall, because root is broken. I followed this instructions:
sudo apt-get remove --purge mysql-server mysql-client mysql-common
sudo apt-get autoremove
sudo apt-get autoclean
But when I install again with
sudo apt-get install mysql-server
Old databases, old users table with broken users, etc.. are here, so it doesn't completely uninstall/repair.