Did you follow this?
https://en.opensuse.org/SDB:LAMP_setup#Configuring_the_MariaDB/MySql_server
To configure the MariaDB server with improved security, please use the script 'mysql_secure_installation provided by openSUSE. Hereafter is the description of the full process.
root # mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!In order to log into MariaDB to secure it, we’ll need the current
password for the root user. If you’ve just installed MariaDB, and
you haven’t set the root password yet, the password will be blank,
so you should just press enter here.Enter current password for root (enter for none):
(Had to switch to the phone. Sorry must stop for today.)