1. 查看当前是否有已经安装好的mysql,先卸载
# 命令
rpm -qa|grep -i mysql
# 结果显示
mysql-community-libs-5.7.42-1.el7.x86_64
mysql-community-common-5.7.42-1.el7.x86_64
mysql-community-libs-compat-5.7.42-1.el7.x86_64
mysql57-community-release-el7-10.noarch
mysql-community-client-5.7.42-1.el7.x86_64
mysql-community-server-5.7.42-1.el7