apt install mysql-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  gstreamer0.10-plugins-base libcdaudio1 libgstreamer-plugins-base0.10-0
  libgstreamer0.10-0 libslv2-9
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  mysql-server-5.7
Suggested packages:
  mailx tinyca
The following NEW packages will be installed:
  mysql-server mysql-server-5.7
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/2,594 kB of archives.
After this operation, 48.5 MB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Preconfiguring packages ...
Selecting previously unselected package mysql-server-5.7.
(Reading database ... 218072 files and directories currently installed.)
Preparing to unpack .../mysql-server-5.7_5.7.12-0ubuntu1_amd64.deb ...
Unpacking mysql-server-5.7 (5.7.12-0ubuntu1) ...
Selecting previously unselected package mysql-server.
Preparing to unpack .../mysql-server_5.7.12-0ubuntu1_all.deb ...
Unpacking mysql-server (5.7.12-0ubuntu1) ...
Processing triggers for systemd (229-4ubuntu4) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up mysql-server-5.7 (5.7.12-0ubuntu1) ...
update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
mysql_upgrade: Got error: 1045: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES) while connecting to the MySQL server
Upgrade process encountered error and will not continue.
mysql_upgrade failed with exit status 11
dpkg: error processing package mysql-server-5.7 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.7; however:
  Package mysql-server-5.7 is not configured yet.

dpkg: error processing package mysql-server (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                       Processing triggers for systemd (229-4ubuntu4) ...
Processing triggers for ureadahead (0.100.0-19) ...
Errors were encountered while processing:
 mysql-server-5.7
 mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)