Access denied for user 'root'@'localhost' (using password: YES) after new installation on Ubuntu

Question

Today I did a login as root into Ubuntu 14.04.1 LTS ll

and then apt-get install mariadb-server (without sudo but as root).

With mySQL -h l

Answer 1

Run mysql_upgrade.

Check that

SHOW GRANTS FOR 'root'@'localhost';

says

GRANT ALL PRIVILEGES ON ... WITH GRANT OPTION 

Check that the table exists _mysql.proxies_priv_.

Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privileges?