安装前看是否安装过mysql，
yum list installed mysql*
如果有就用yum remove卸载mysql
查看yum库下是否有mysql-server
yum list | grep mysql 或 yum -y list mysql*
如果没有（一般在centos7下没有）
wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm
rpm -ivh mysql-community-release-el7-5.noarch.rpm
然后安装mysql
yum install mysql-server
yum install mysql-devel
然后在mysql配置文件/etc/my.cnf的[mysqld]中加入character-set-server=utf8 然后启动mysql服务 /bin/systemctl start mysqld.service 登录mysql mysql -u root -p 刚安装密码为空，直接按回车 切换到mysql数据库：use mysql; 然后修改密码UPDATE user SET password=password("你的密码") WHERE user='root'; 刷新权限 FLUSH PRIVILEGES;
