How do I uninstall MariaDB on Ubuntu 14.04 (Trusty Tahr)?

There are a few other options which might be of use:

sudo apt-get remove mariadb-server

This will remove just the mariadb-server package itself.

sudo apt-get remove --auto-remove mariadb-server

This will remove the mariadb-server package and any other dependant packages which are no longer needed.

If you also want to delete your local/config files for mariadb-server then this will work.

sudo apt-get purge --auto-remove mariadb-server

but be careful with that last one. See the disclaimer at the installion site