Upgraded a 16.04 LTS HTPC box (running for some years) to 18.04 LTS

Failed miserably; keyboard not working, mysql login failed, gave up.

New 18.04 LTS install. dist-upgrade and installed LAMP stack.

Tested mysql>

Noted mysql login from command line failed. STuffed around on the 'net troubleshooting for several hours. Finally worked out there is no default password on mysql. Evenutally got to mysql from command line and set up 'root'@'localhost' plus two other users, all with GRANT ALL using PASSWORD. Coool. Worked ok from command line.

Tried mythtv; no access to database (???)

Tried client (phpmyadmin and mysql-workbench) on localhost - "Access denied for user root@localhost'

Tried login from shell. All good.

So I can login OK from the command line but no other client software on localhost has access to mysql. WTF??

There is nothing left on the web to help me on why the command line mysql login works but other mysql clients fail.

Any help, anyone?

You need to issue explicit grant statements
due to possibly running or have run (installer) of mysql_secure_installation Section 2.10, “Postinstallation Setup and Testing”.

Search for mysql at https://help.ubuntu.com and have at it.

Thanks. I'll bear it in mind next time.

However, the issue was the lack of a password for mysql root. I eventually managed to assign one from the command line. phpmyadmin & mysql-workbench worked after that </sigh> - I've since read there are supposed to be settings in phpmyadmin workbench to log in with password less user accounts. I couldn't find them.

Regarding the mythtv backend login, there's a bit of a gotcha; the installer assigns a random password to mysql user mythtv. However, in the initial setup and user account it issues 'mythtv' as the password. The correct password can be seen in /home/mythtv/.mythtv/config.xml

Copying /home/mythtv/.mythtv/config.xml to /home/<user>/.mythtv/config.xml BEFORE running mythtv backend configuration resolves the issue.