CentOS 7 come with MariaDB, a drop-in replacement for MySQL. In some cases, you need to install the Oracle MySQL server.
Download and install MySQL repository
rpm -ivh http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm
Next, you can install the MySQL server by running the command
yum install mysql-community-server
Enable MySQL to start on boot
systemctl enable mysqld
Start MySQL with
systemctl start mysqld
To secure MySQL run
mysql_secure_installation
