auser@nix:~$ sudo apt-get install mariadb-server php-mysql
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following package was automatically installed and is no longer required:
  libevent-core-2.0-5
Use 'sudo apt autoremove' to remove it.
The following additional packages will be installed:
  mariadb-client-10.0 mariadb-client-core-10.0 mariadb-server-10.0
  mariadb-server-core-10.0
Suggested packages:
  mailx mariadb-test tinyca
The following packages will be REMOVED:
  mysql-client-5.7 mysql-client-core-5.7 mysql-server-core-5.7
The following NEW packages will be installed:
  mariadb-client-10.0 mariadb-client-core-10.0 mariadb-server mariadb-server-10.0
  mariadb-server-core-10.0 php-mysql
0 upgraded, 6 newly installed, 3 to remove and 0 not upgraded.
Need to get 0 B/14,2 MB of archives.
After this operation, 24,1 MB of additional disk space will be used.
Do you want to continue? [Y/n] 
Preconfiguring packages ...
(Reading database ... 202882 files and directories currently installed.)
Removing mysql-client-5.7 (5.7.17-0ubuntu0.16.04.1) ...
Removing mysql-client-core-5.7 (5.7.17-0ubuntu0.16.04.1) ...
Removing mysql-server-core-5.7 (5.7.17-0ubuntu0.16.04.1) ...
Processing triggers for man-db (2.7.5-1) ...
Selecting previously unselected package mariadb-client-core-10.0.
(Reading database ... 202738 files and directories currently installed.)
Preparing to unpack .../mariadb-client-core-10.0_10.0.29-0ubuntu0.16.04.1_i386.deb ...
Unpacking mariadb-client-core-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Selecting previously unselected package mariadb-client-10.0.
Preparing to unpack .../mariadb-client-10.0_10.0.29-0ubuntu0.16.04.1_i386.deb ...
Unpacking mariadb-client-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Selecting previously unselected package mariadb-server-core-10.0.
Preparing to unpack .../mariadb-server-core-10.0_10.0.29-0ubuntu0.16.04.1_i386.deb ...
Unpacking mariadb-server-core-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Selecting previously unselected package mariadb-server-10.0.
Preparing to unpack .../mariadb-server-10.0_10.0.29-0ubuntu0.16.04.1_i386.deb ...
/var/lib/mysql: found previous version 10.0
Unpacking mariadb-server-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Selecting previously unselected package mariadb-server.
Preparing to unpack .../mariadb-server_10.0.29-0ubuntu0.16.04.1_all.deb ...
Unpacking mariadb-server (10.0.29-0ubuntu0.16.04.1) ...
Selecting previously unselected package php-mysql.
Preparing to unpack .../php-mysql_1%3a7.0+35ubuntu6_all.deb ...
Unpacking php-mysql (1:7.0+35ubuntu6) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for systemd (229-4ubuntu16) ...
Processing triggers for ureadahead (0.100.0-19) ...
Setting up mariadb-client-core-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Setting up mariadb-client-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Setting up mariadb-server-core-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Setting up mariadb-server-10.0 (10.0.29-0ubuntu0.16.04.1) ...
Setting up mariadb-server (10.0.29-0ubuntu0.16.04.1) ...
Setting up php-mysql (1:7.0+35ubuntu6) ...
auser@nix:~$ mysql -u root -p
Enter password: 
ERROR 1698 (28000): Access denied for user 'root'@'localhost'