CentOS 7版本下载
    rpm -Uvh https://repo.mysql.com//yum/mysql-5.7-community/el/7/x86_64/mysql57-community-release-el7-10.noarch.rpm
    https://repo.mysql.com//yum/mysql-8.0-community/el/7/x86_64/mysql80-community-release-el7-3.noarch.rpm

    [root@localhost ~]#yum list
    [root@localhost ~]#yum -y install mysql-community-server
    [root@localhost ~]#systemctl start mysqld
    [root@localhost ~]#systemctl enable mysqld
    [root@localhost ~]# lsof -i :3306
    第一次通过# grep “password” /var/log/mysqld.log 命令获取MySQL的临时密码
    [root@localhost ~]# grep “password” /var/log/mysqld.log
    2018-05-24T09:51:57.585660Z 1 [Note] A temporary password is generated for root@localhost: sJ?dm)NB2%o+
    用该密码登录到服务端后，必须马上修改密码，不然操作查询时报错误
    刚开始设置的密码必须符合长度，且必须含有数字，小写或大写字母，特殊字符。
    如果想设置简单密码，如下操作：
    方法一：首先，修改validate_password_policy参数的值
    mysql> set global validate_password_policy=0; #定义复杂度
    mysql> set global validate_password_length=1; #定义长度 默认是8
    mysql> set password for ‘root’@’localhost’=password(‘311311’);
    mysql> flush privileges;
    方法二：在/etc/my.cnf 可关闭密码强度审计插件，重启mysql服务
    validate-password=ON/OFF/FORCE/FORCE_PLUS_PERMANENT: 决定是否使用该插件(及强制/永久强制使用)。

    方法三：mysql> alter user user() identified by ‘>F.BT,r%n123’;
    mysql> flush privileges;

    查看安装后的文件
    [root@localhost ~]# rpm -qa | grep mysql
    mysql-community-server-5.7.22-1.el7.x86_64
    mysql57-community-release-el7-10.noarch
    mysql-community-common-5.7.22-1.el7.x86_64
    mysql-community-client-5.7.22-1.el7.x86_64
    mysql-community-libs-compat-5.7.22-1.el7.x86_64
    mysql-community-libs-5.7.22-1.el7.x86_64
    [root@localhost ~]# rpm -ql mysql-community-server-5.7.22-1.el7.x86_64
    /etc/logrotate.d/mysql
    /etc/my.cnf
    /usr/sbin/mysqld
    /var/lib/mysql
    /var/lib/mysql-files
    /var/run/mysqld