Default install:

```bash
MariaDB [(none)]> SELECT host, user, password, plugin FROM mysql.user LIMIT 0,1;
+-----------+------+----------+-------------+
| host      | user | password | plugin      |
+-----------+------+----------+-------------+
| localhost | root |          | unix_socket |
+-----------+------+----------+-------------+
1 row in set (0.00 sec)
```
To remove:
```bash
UPDATE mysql.user SET plugin = '' WHERE user = 'root' AND host = 'localhost';
```

To add password:
```bash
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('mySecretPassword');
FLUSH PRIVILEGES;
```