一、卸载本地 Mysql

//1、查看本地mysql依赖情况dpkg --list | grep mysql//2.卸载mysql-commonsudo apt remove mysql-common//3.卸载并清除mysql5.7sudo apt autoremove --purge mysql-server-5.7//4.清除残留数据dpkg -l | grep ^rc| awk '{print$2}'| sudo xargs dpkg -P//5.再次检查依赖项情况dpkg --list | grep mysql//6.再次执行删除sudo apt autoremove --purge mysql-apt-config

二、安装 mysql5.7

下载MySQL apt存储库

//1、使用wget下载tar包wget https://downloads.mysql.com/archives/get/p/23/file/mysql-server_5.7.36-1ubuntu18.04_amd64.deb-bundle.tar//2、在目录下解压tar包tar xvf ./mysql-server_5.7.36-1ubuntu18.04_amd64.deb-bundle.tar//安装依赖lib包sudo apt-get install ./libmysql*
sudo apt-get install libtinfo5//安装客户端和服务端 ； 过程中会提示设置MySQL的密码，用户名默认rootsudo apt-get install ./mysql-community-client_5.7.36-1ubuntu18.04_amd64.deb
sudo apt-get install ./mysql-client_5.7.36-1ubuntu18.04_amd64.deb
sudo apt-get install ./mysql-community-server_5.7.36-1ubuntu18.04_amd64.deb
sudo apt-get install ./mysql-server_5.7.36-1ubuntu18.04_amd64.deb //启动mysql  ； 绿色的active表示运行中systemctl status mysql.service//登录Mysqlmysql -u root -p//退出
exit//安装成功，可以选择删除安装包sudo rm -rf /安装包所在目录（不能是根目录）