step1:下载mysql源安装包：wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
step2:安装MySQL源：yum localinstall mysql57-community-release-el7-8.noarch.rpm
step3:检测是否安装完成:yum repolist enabled | grep “mysql.-community.”
step4:安装mysql:yum install mysql-community-server
step5:验证: mysqladmin --version
step6:重启服务 systemctl restart mysqld
step7:查看初始密码； grep “password” /var/log/mysqld.log
step8:利用初始密码进入mysql:mysql -u root -p
step9:修改密码: alter user ‘root’@‘localhost’ indetified by ‘新密码’;
注意:可能出现
原因是密码等级太简单，如果你坚持要这样的密码，要改变密码等级(具体看
https://blog.csdn.net/qq_44766883/article/details/104316061)：
mysql> set global validate_password_policy=0; //改变密码等级
mysql> set global validate_password_length=4; //改变密码最小长度
之后再进行修改密码就可以了
