For my surprise, after installing MySQL server, there was no service mysqld in /etc/init.d, so I could not start mysql server with the command /etc/init.d/mysqld start
So it seems that now, to start a service we must run the command systemctl.
In case you want to enable the mysql when you start your computer:
Another thing that hit me by surprise is that phpMyAdmin doesn’t work out of the box, you need to configure some options.
Edit the files /etc/httpd/conf.d/phpMyAdmin.conf and /etc/phpMyAdmin/config.inc.php (main one).
In my case, I set a random string to the blowfish_secret option, changed auth_type to cookie instead of the default http, and changed to TRUE the option to allow no password (AllowNoPassword).
After a restart of the apache server (# systemctl restart httpd.service), I was ready to go.