由於CentOS7默認的數據庫yum源切換成了MariaDB，需要手動設置yum源纔可安裝mysql。
1、安裝yum源
# rpm -Uvh http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
2、檢測可用的yum源
# yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64 MySQL Connectors Community
mysql-tools-community/x86_64 MySQL Tools Community
mysql56-community/x86_64 MySQL 5.6 Community Server
3、yum安裝mysql
# yum -y install mysql-community-server
4、加入開機啓動
# systemctl enable mysqld
5、啓動mysqld
# systemctl start mysqld