ubuntu16.04 完全卸載MySQL

sudo apt-get autoremove --purge mysql-server-5.7 
#sudo apt-get remove mysql-server         # 沒用到,已經沒有mysql-server
#sudo apt-get autoremove mysql-server  # 沒用到,已經沒有mysql-server
sudo apt-get remove mysql-common
sudo rm -rf /etc/mysql/  /var/lib/mysql    #很重要
#清理殘留數據
dpkg -l |grep ^rc|awk '{print $2}' |sudo xargs dpkg -P  
sudo apt autoremove
sudo apt autoreclean

安裝MySQL:

sudo apt-get install mysql-server
sudo apt-get install mysql-client
sudo apt-get install libmysqlclient-dev

啓動、關閉服務和查看運行狀態

sudo service mysql start
sudo service mysql stop
sudo service mysql status