Attempting mysql -u root fails with Access denied for user 'root'@'localhost immediately after doing brew install mariadb and starting mariadb with brew services start mariadb.
To fix it (with MariaDB still running):
sudo mysqlthen enter your Mac user passwordALTER USER 'root'@'localhost' IDENTIFIED BY 'newrootpassword';replacingnewrootpasswordwith the password you wish to use for the MariaDB root user.- Ctrl-C to exit mysql.
You should then be able to connect to MariaDB with mysql -u root -p, then entering the root password when prompted.