1 - 创建文件/etc/apt/sources.list.d/pgdg.list并为存储库添加一行
deb [arch=amd64] http://apt.postgresql.org/pub/repos/apt/ focal-pgdg main
2 - 导入存储库签名密钥，并更新软件包列表
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
sudo apt-get update
3-安装 posgtresql
sudo apt-get install postgresql-12 postgresql-client-12 postgresql-12 postgresql-contrib libpq-dev postgresql-server-dev-12
4 - 安装 pgadmin 4
sudo apt-get install pgadmin4
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package pgadmin4 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'pgadmin4' has no installation candidate