[请注意，我无法在Ubuntu上安装mysql-server。这就是我所看到的。
user@MyServer:~/Install$ sudo apt-get install mysql-server mysql-client
Reading package lists... Done
Building dependency tree
Reading state information... Done
mysql-server is already the newest version (5.7.29-0ubuntu0.16.04.1).
The following NEW packages will be installed:
mysql-client
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
Need to get 10.1 kB of archives.
After this operation, 110 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Get:1 http://ca.archive.ubuntu.com/ubuntu xenial-updates/main amd64 mysql-client all 5.7.29-0ubuntu0.16.04.1 [10.1 kB]
Fetched 10.1 kB in 0s (32.6 kB/s)
Selecting previously unselected package mysql-client.
dpkg: warning: files list file for package 'apache2-bin' missing; assuming package has no files currently installed
(Reading database ... 365868 files and directories currently installed.)
Preparing to unpack .../mysql-client_5.7.29-0ubuntu0.16.04.1_all.deb ...
Unpacking mysql-client (5.7.29-0ubuntu0.16.04.1) ...
Setting up mysql-server-5.7 (5.7.29-0ubuntu0.16.04.1) ...
Renaming removed key_buffer and myisam-recover options (if present)
mysql_upgrade: Got error: 1524: Plugin 'unix_socket' is not loaded 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
Setting up mysql-client (5.7.29-0ubuntu0.16.04.1) ...
No apport report written because the error message indicates its a followup error from a previous failure.
Errors were encountered while processing:
mysql-server-5.7
mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)
到目前为止，我一直在研究这些链接，但没有发现任何有用的信息。
https://computingforgeeks.com/how-to-solve-error-1524-hy000-plugin-unix_socket-is-not-loaded-mysql-error-on-debian-ubuntu/Issues on reinstalling MySQL 5.7 server on Ubuntu 16.04Issue installing mysql server on ubuntu 16.04
有人有什么建议吗？ TIA。
这似乎是您从以前的MariaDB安装中安装MySQL。
不支持这种形式的安装。建议从MariaDB中转储数据（使用在数据目录上运行的mariadb）（mysqldump）并手动移植mysql。*表内容（创建用户和grants，备份并移动/ var / lib / mysql数据目录，然后重试安装。
或者继续使用MariaDB。