I had this same problem. My phpmyadmin login did not allow me to see the wordpress databases. I searched through where I took notes on the original phpmyadmin install and found that I had saved a password:
rootmysqlpass = 'some password' (mine was long). I must have gotten this from the console while installing and, not knowing what it was, just saved it just in case.
I went back to the phpmyadmin login and instead of logging in as 'phpmyadmin', I logged in as root and cut and pasted the rootmysqlpass that I had saved. It worked and I had access to the wordpress databases. also i could go to user accounts and edit the privileges for phpmyadmin. I just checked the box "Global Privileges" and then clicked "go". Then when I logged out and logged in as phpmyadmin again I could see the databases and had all the privileges needed.
If you DO NOT have your rootmysqlpass anywhere, there is another solution I found in my searches. With FTP, (I use FileZilla it is great!), you can navigate to etc>mysql and there is a file in there called "debian.cnf". Open it and you will see a user, (mine was "debian-sys-mint") and a password. You can login to phpmyadmin with that user and password and you will see the wordpress databases. You can then go and change the privileges for the user "phpmyadmin" just like if you logged in as the root user.
I hope this helps and saves someone 2 hours of the time I just spent figuring this out.
