Linux下卸载重装MySQL（基于CentOS8）

背景：卸载宝塔面板后，MySQL服务起不来，尝试修复无果，直接重装

1.卸载MySQL组件

$ rpm -e --nodeps mysql-community-common
$ rpm -e --nodeps mysql-community-libs
$ rpm -e --nodeps mysql-community-libs-compat
$ rpm -e --nodeps mysql-community-client
$ rpm -e --nodeps mysql-community-server

2.检查是否卸载干净

$ rpm -qa | grep -i mysql

3.查看mysql相关文件

$ whereis mysql

4.删除mysql相关文件

$ rm -rvf /usr/lib64/mysql*
$ rm -rvf /usr/include/mysql*
$ rm -rvf /usr/share/mysql*

5.查找mysql文件

$ find / -name mysql

6.删除相关文件

$ rm -rvf /var/lib/selinux/targeted/active/modules/100/mysql*
$ rm -rvf /var/lib/selinux/targeted/tmp/modules/100/mysql*
$ rm -rvf /var/lib/mysql*
$ rm -rvf /usr/share/bash-completion/completions/mysql*
$ rm -rvf /usr/share/selinux/targeted/default/active/modules/100/mysql*

7.重新安装MySQL组件

$ sudo rpm -ivh mysql-community-common-5.7.28-1.el7.x86_64.rpm 
$ sudo rpm -ivh mysql-community-libs-5.7.28-1.el7.x86_64.rpm
$ sudo rpm -ivh mysql-community-libs-compat-5.7.28-1.el7.x86_64.rpm
$ sudo rpm -ivh mysql-community-client-5.7.28-1.el7.x86_64.rpm
$ sudo rpm -ivh mysql-community-server-5.7.28-1.el7.x86_64.rpm

8.初始化数据库

$ sudo mysqld --initialize --user=mysql

9.查看临时生成的root用户的密码

$ sudo grep 'temporary password' /var/log/mysqld.log
# vhep<My(Z0hx

10.启动 MySQL 服务

$ sudo systemctl start mysqld

11.登录 MySQL 数据库

$ mysql -uroot -p
 密码：vhep<My(Z0hx

12.修改数据库root用户的登录密码

mysql> set password = password("000000");

MySQL8版本:

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '000000';

-- 更新权限表: 更新权限表，使更改生效
FLUSH PRIVILEGES;

-- 重启MySQL服务
sudo systemctl restart mysqld

13.修改 mysql 库下的user表中的 root 用户允许任意 ip 连接

mysql> update mysql.user set host='%' where user='root'; 
mysql> flush privileges;