Step1: 检测系统是否自带安装mysql
yum list installed | grep mysql

Step2: 删除系统自带的mysql及其依赖
yum -y remove mysql-libs.x86_64

Step3: 给CentOS添加rpm源，并且选择较新的源

在MySQL官网中下载YUM源rpm安装包：
https://dev.mysql.com/downloads/repo/yum/
centos7下载：Red Hat Enterprise Linux 7 / Oracle Linux 7 (Architecture Independent), RPM Package
centos6下载：Red Hat Enterprise Linux 6 / Oracle Linux 6 (Architecture Independent), RPM Package

下载yum源
wget https://repo.mysql.com//mysql80-community-release-el7-7.noarch.rpm
安装mysql源
yum localinstall mysql80-community-release-el7-7.noarch.rpm

修改源
vim /etc/yum.repos.d/mysql-community.repo
改变默认安装的mysql版本。比如要安装5.7版本，将5.7源的enabled=0改成enabled=1。然后再将其他版本如8.0版本的enabled=1改成enabled=0即可

开始安装
yum install mysql-community-server