sudo pacman -S mariadb
initialized data
sudo mariadb-install-db --user=mysql --basedir=/usr --datadir=/var/lib/mariadb
if failed
sudo rm -rf /var/lib/mysql
sudo rm -rf /var/lib/mariadb
and do initalized again
after that you can
sudo mariadb-secure-installation
Optional, service:
sudo systemctl start mariadb
sudo systemctl enable mariadb
sudo systemctl status mariadb