Versions 10 and higher of Plesk have the administration password encrypted on the server. As a result, if you do not know the password, you cannot log into the MySQL database with administration powers.
However, you can get the administration password from a command line:
/usr/local/psa/bin/admin --show-password
And now that you know the password, you can log into MySQL with root administration privileges on any version of Plesk with this command line:
mysql -uadmin –p’cat /etc/psa/.psa.shadow’
This command gives you access to the MySQL database on the server.