Ubuntu重装mysql错误解决

新搭建的服务器，先在Ubuntu上安装mariadb，后来由于很多权限问题，决定安装Mysql,在卸载过程中由于未卸载干净，导致mysql重装过程中出现了很多问题。

Reading package lists...Done
Building dependency tree
Reading state information ... Done
mysql-server is already the newest version(5.7.21-0ubuntu0.16.04.1).
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
mysql-server: depends: mysql-server-5.7 but it is not going to be installed
E: Unmet dependencies.Try 'apt-get -f install' with no packages(or specify a solution).

通过阅读错误信息可知，主要是因为依赖关系出现问题，主要思路是重建依赖关系，然后干净卸载，最后重装。

首先，更新系统

sudo apt-get update

然后，修复安装错误，会提示输入mysql用户名密码

sudo apt-get --fix-broken install

然后，检索mysql安装包，并删除检索出的依赖包，然后是删除/var/lib/mysql,最后重装mysql。

下面我把检索到的解决方法展示给大家：

We excute the following commands to solve the above problem:
    1.Get the list of MySQL packages installed on the system by executing the command sudo dpkg -l grep mysql
    2.Remove the packages shown above by executing the command 
      sudo apt-get --purge autoremove <packages from the step 1>
    3. Delete /var/lib/mysql
    4.Try to install mysql again.It should solve your problem.

第二步中的packages如下图所示：

最后就是更新系统并重装mysql

sudo apt-get update
sudo apt-get install mysql-server mysql-client

 总结：

整体思路还是重建依赖关系，干净卸载，更新安装。希望对遇到相同问题不知所措的小伙伴有所启发、帮助。谢谢。