Assuming, MySQL is running on ‘remoteserver’ on 127.0.0.1:3306, and you have only SSH access to the remote server.
lexus@lexus:~$ ssh user@remote-server -L 3306:127.0.0.1:3306 -N
support@remote-server’s password: (press Ctrl-Z)
^Z
[1]+ Stopped ssh user@remote-server -L 3306:127.0.0.1:3306 -N
lexus@lexus:~$ bg
[1]+ ssh user@remote-server -L 3306:127.0.0.1:3306 -N &
lexus@lexus:~$ mysql -h 127.0.0.1 -p -u sqluser
Enter password:
Tags: port fowarding, ss