在Ubuntu的衍生版linux系统中一般使用sudo apt-get install mariadb-server安装MariaDB，但是安装完后，可能会存在用普通用户连接MariaDB报错的情况，如下：

jzk@jzk-PC:/etc/mysql$ mysql -u root

ERROR 1698 (28000): Access denied for user 'root'@'localhost'

解决办法如下：

jzk@jzk-PC:/etc/mysql$ sudo mysql -uroot

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 31

Server version: 10.1.29-MariaDB-6+b1 Debian buildd-unstable

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> use mysql;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

MariaDB [mysql]> update user set plugin='' where user='root';

Query OK, 1 row affected (0.00 sec)

Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [mysql]> flush privileges;

Query OK, 0 rows affected (0.00 sec)

MariaDB [mysql]> exit;

Bye

jzk@jzk-PC:/etc/mysql$ mysql -u root

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 32

Server version: 10.1.29-MariaDB-6+b1 Debian buildd-unstable

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.