去mysql官网下载MySQL安装程序(for Linux)，网址：https://dev.mysql.com/downloads/mysql/
       将MySQL程序(如：mysql-5.7.21-1.el7.x86_64.rpm-bundle.tar)上传到服务器的/opt/dzgd/目录。

使用命令解压缩该文件，tar –xf mysql-5.7.21-1.el7.x86_64.rpm-bundle.tar

使用命令查询已安装的mysql模块，rpm –qa | grep mariadb

使用命令删除系统自带的mariadb，rpm –e --nodeps mariadb-libs-5.5.52-1.el7.x86_64

安装MySQL：

rpm –ivh mysql-community-common-5.7.21-1.el7.x86_64.rpm

rpm –ivh mysql-community-libs-5.7.21-1.el7.x86_64.rpm

rpm –ivh mysql-community-client-5.7.21-1.el7.x86_64.rpm

rpm –ivh mysql-community-server-5.7.21-1.el7.x86_64.rpm

rpm –ivh mysql-community-devel-5.7.21-1.el7.x86_64.rpm

设置数据库初始密码：

mysql –u root –p –P 3307 –h 127.0.0.1

set password=password(‘xxxxxxxxxxx’);

在线安装

wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm

rpm -ivh mysql-community-release-el7-5.noarch.rpm

yum install mysql-server

yum install mysql-devel