一、卸载mysql

安装依赖：yum install libaio wget -y

检查MYSQL是否已安装：yum list installed | grep mysql

删除所有的mysql相关的包：yum remove 包名(需要手动一个个移除包)

例子：

[root@VM_0_14_centos log]# yum list installed | grep mysql

Repository epel is listed more than once in the configuration

mysql-community-client.x86_64          8.0.21-1.el7                   @mysql80-community

mysql-community-common.x86_64          8.0.21-1.el7                   @mysql80-community

mysql-community-libs.x86_64            8.0.21-1.el7                   @mysql80-community

mysql-community-server.x86_64          8.0.21-1.el7                   @mysql80-community

mysql80-community-release.noarch       el7-1                          @/mysql80-community-release-el7-1.noarch

[root@VM_0_14_centos log]# yum remove mysql-community-client.x86_64

[root@VM_0_14_centos log]# yum remove mysql-community-common.x86_64

[root@VM_0_14_centos log]# yum remove mysql-community-server.x86_64

[root@VM_0_14_centos log]# yum remove mysql80-community-release.noarch

二、安装mysql仓库文件

在官网找到对应的mysql 的rpm包：https://repo.mysql.com/

下载仓库文件：wget https://repo.mysql.com/mysql80-community-release-el7.rpm

安装仓库文件: yum localinstall mysql80-community-release-el7.noarch.rpm

验证是否安装成功：yum repolist enabled | grep "mysql.*-community.*"

三、安装mysql

安装mysql:  yum install mysql-community-server -y

执行：rpm -qi mysql-community-server.x86_64 0:8.0.16-2.el7

查看安装的mysql:  whereis mysql

mysql服务命令：

systemctl start mysqld  启动

systemctl enable mysqld 自启

systemctl status mysqld  状态

service mysqld restart  重启

四、如何查看初始化密码

执行命令：grep "temporary password" /var/log/mysqld.log

实例：

[root@VM_0_14_centos]# grep "temporary password" /var/log/mysqld.log

2020-05-08T00:10:26.660473Z 6 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: V>/.nvoWb1ua

五、如何修改密码

1、vim /etc/my.cnf 的mysqld下添加skip-grant-tables

2、重启mysql服务：service mysqld restart

3、进入数据库：mysql

4、置空密码: update user set authentication_string = ‘’ where User = ‘root’;

5、退出数据库：exit;

6、修改文件 vim /etc/my.cnf 的mysqld下注释skip-grant-tables

7、保持并退出：wq!

8、重启服务：service mysqld restart

9、执行命令：mysql -u root -p

10、提示输入密码直接敲回车即可进入mysql数据库

11、更改密码：alter user  "root"@"localhost" IDENTIFIED BY "xxxxx.>2020"

注：密码格式要符合当前策略否则会提示

mysql> ERROR 1819 (HY000): Your password does not satisfy the current policy requirements