Failed to install libgdal on ubuntu 20.04.2 server

it is not 'universe repo' problem, this post was suggested by forum member How do I enable the "Universe" repository?. It is because missing some depends, see the answer below.

How to install libgdal on ubuntu 20.04.2 server? I got the following errors:

$ sudo apt install libgdal-dev

...
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libgdal-dev : Depends: default-libmysqlclient-dev but it is not going to be installed

The following solutions not works for me:

• add extra ppa (see answer-1)

• install extra .deb (see answer-2)

According to @N0rbert 's advice, here are the output of the command:

$ apt-cache policy libgdal-dev libmysqlclient-dev default-libmysqlclient-dev
libgdal-dev:
  Installed: 3.0.4+dfsg-1build3
  Candidate: 3.0.4+dfsg-1build3
  Version table:
 *** 3.0.4+dfsg-1build3 500
        500 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal/universe amd64 Packages
        500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status
libmysqlclient-dev:
  Installed: 8.0.25-0ubuntu0.20.04.1
  Candidate: 8.0.25-0ubuntu0.20.04.1
  Version table:
 *** 8.0.25-0ubuntu0.20.04.1 500
        500 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates/main amd64 Packages
        500 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-security/main amd64 Packages
        100 /var/lib/dpkg/status
     8.0.19-0ubuntu5 500
        500 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal/main amd64 Packages
     5.7.34-1ubuntu18.04 500
        500 http://repo.mysql.com/apt/ubuntu bionic/mysql-5.7 amd64 Packages
default-libmysqlclient-dev:
  Installed: 1.0.5ubuntu2
  Candidate: 1.0.5ubuntu2
  Version table:
 *** 1.0.5ubuntu2 500
        500 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal/main amd64 Packages
        100 /var/lib/dpkg/status

Add apt info here

$ grep -r "^deb" /etc/apt/ --include=*.list
/etc/apt/sources.list.d/mysql.list:deb http://repo.mysql.com/apt/ubuntu/ bionic mysql-apt-config
/etc/apt/sources.list.d/mysql.list:deb http://repo.mysql.com/apt/ubuntu/ bionic mysql-5.7
/etc/apt/sources.list.d/mysql.list:deb http://repo.mysql.com/apt/ubuntu/ bionic mysql-tools
/etc/apt/sources.list.d/mysql.list:deb-src http://repo.mysql.com/apt/ubuntu/ bionic mysql-5.7
/etc/apt/sources.list.d/linuxuprising-ubuntu-libpng12-focal.list:deb http://ppa.launchpad.net/linuxuprising/libpng12/ubuntu focal main
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal universe
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates universe
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal multiverse
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates multiverse
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security universe
/etc/apt/sources.list:deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security multiverse
/etc/apt/sources.list:deb https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/
/etc/apt/sources.list:deb http://archive.ubuntu.com/ubuntu focal universe

It turns out that this lib is required libmysqlclient-dev for libgdal, and I should install it manually first.

$ sudo apt update
$ sudo apt install libmysqlclient-dev
$ sudo apt install libgdal-dev

Check the installation:

$ gdalinfo --version
GDAL 3.0.4, released 2020/01/28