ResolutionParallels Plesk Panel renames 'root' mysql account to 'admin' when the Panel is installed.
To get root privileges in mysql simply login with the 'admin' username instead. The password is the same as the admin password in Parallels Plesk Panel.
On server with Parallels Plesk Panel versions 8.x, 9.x and above admin password is stored in file /etc/psa/.psa.shadow. Use the following command to get the password:
~# cat /etc/psa/.psa.shadow
Since version 10 admin password stored in file /etc/psa/.psa.shadow is encrypted. Use the following command to get admin password in plain text:
~# /usr/local/psa/bin/admin --show-password
Despite version of Parallels Plesk Panel you may use the following command to login to mysql with root privileges:
~# mysql -uadmin -p`cat /etc/psa/.psa.shadow`