# 下载mysql源安装包
wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
如果报错（-bash: wget: command not found），则：安装wget
yum -y install wget
# 安装mysql源
yum localinstall mysql57-community-release-el7-8.noarch.rpm
检查mysql源是否安装成功
yum repolist enabled | grep "mysql.*-community.*"
