To install mysql as a service, run the following commands from the support-files directory in the installation. In my case /usr/local/mysql/support-files

$ cp mysql.server /etc/init.d/mysql
$ chmod +x /etc/init.d/mysql
$ chkconfig --add mysql
$ systemctl enable mysql

Then, you can simply start mysql with the following command.

$ sudo /etc/init.d/mysql start