第一步：安裝從網上下載文件的wget命令
[root@localhost ~]# yum -y install wget
第二步：下載mysql的repo源
[root@localhost ~]# wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm
第三步：安裝mysql-community-release-el7-5.noarch.rpm包
[root@localhost ~]# rpm -ivh mysql-community-release-el7-5.noarch.rpm
第四步：查看確認下
[root@localhost ~]# ls -l /etc/yum.repos.d/mysql-community*
/etc/yum.repos.d/mysql-community.repo
/etc/yum.repos.d/mysql-community-source.repo
會獲得兩個mysql的yum repo源：/etc/yum.repos.d/mysql-community.repo，/etc/yum.repos.d/mysql-community-source.repo。
第五步：安裝mysql
[root@localhost ~]# yum install mysql-server