apache2，mysql的依赖问题-常见的libmysqlclient20 20: and 64和libmysqlclient20 5.7

Question

我试图安装一个软件包，但依赖项存在某种问题。首先，我尝试使用sudo apt-get autoremove命令清理所有内容，并得到了与apt-get install类似的错误消息。

自动移除后输出

Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
4 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up apache2 (2.4.18-2ubuntu3.5) ...
info: Executing deferred 'a2enconf javascript-common' for package javascript-common
ERROR: Conf javascript-common does not exist!
dpkg: error processing package apache2 (--configure):
subprocess installed post-installation script returned error exit status 1
Setting up mysql-common (5.7.20-0ubuntu0.16.04.1) ...
update-alternatives: error: alternative path /etc/mysql/my.cnf.fallback doesn't exist
dpkg: error processing package mysql-common (--configure):
subprocess installed post-installation script returned error exit status 2
dpkg: dependency problems prevent configuration of libmysqlclient20:amd64:
libmysqlclient20:amd64 depends on mysql-common (>= 5.5); however:
Package mysql-common is not configured yet.

dpkg: error processing package libmysqlclient20:amd64 (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of mysql-client-5.7:
 mysql-client-5.7 depends on mysql-common (>= 5.5); however:
 Package mysql-common is not configured yet.

dpkg: error processing package mysql-client-5.7 (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                      No apport report written because MaxReports is reached already
Errors were encountered while processing:
 apache2
 mysql-common
 libmysqlclient20:amd64
 mysql-client-5.7
E: Sub-process /usr/bin/dpkg returned an error code (1)

有什么解决办法吗？包apache2、mysql-common等似乎有一些问题，但我不知道，因为我对命令行不太熟悉。

Answer 1

首先，如果您有一些有价值的数据，请对数据库进行备份。

备份可以用

mysqldump -u{username} -p{password} {database_name} > {desired_file_name}.sql

请注意，-u和username之间以及-p和password之间没有空格。

然后彻底清除mysql并在需要时重新安装它。

您可以找到如何清除mysql 这里或这里。