Ubuntu can't completely remove and install MySQL problem
The installation usually exits unexpectedly, or it is difficult to delete MySQL and install it again, except for problems during the operation of MySQL. After experiments, the following steps can effectively solve the above problems.
首先删掉 /etc/mysql 和 /var/lib/mysql 这两个文件夹，这里存放的是MySQL的配置文件
sudo rm -rf /etc/mysql
sudo rm -rf /var/lib/mysql
sudo apt-get autoremove mysql-server* --purge
图形界面确认删除
sudo apt-get autoclean
sudo apt-get remove apparmor
再从新安装MySQL