Ubuntu18.04 Install Postgres 12 Database

Why install PostgreSQL 12

PostgreSQL 12 has many new features, but the key point is that SQL backup files from PostgreSQL 12 cannot be directly imported into PostgreSQL 10 using the psql command.
The default installation method on Ubuntu 18.04, apt install postgresql, installs PostgreSQL 10, which can cause some trouble when restoring the database.
Therefore, it is best to install PostgreSQL 12 directly in one step.
On Ubuntu 20.04, using apt install postgresql installs PostgreSQL 12 by default.

Installation command

# Add PostgreSQL source to system sources
sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'

# Add signing key
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -

# Update package list
# Before this, you can replace the software sources with domestic ones
sudo apt-get update

# Install the latest version of PostgreSQL
# To specify a version, use a command like postgresql-12 (postgresql-version number):
sudo apt-get install postgresql