I put it like this:
sudo apt install postgresql postgresql-contrib
How to fix it?
Answer 1, authority 100%
First, what does the command do?
sudo service postgresql status
Remove everything
sudo apt --purge remove postgresql-12 postgresql-client-12 postgresql-client-common postgresql-common
Then
sudo rm -rf / var / lib / postgresql /
sudo rm -rf / var / log / postgresql /
sudo rm -rf / etc / postgresql /
sudo userdel -r postgres
sudo groupdel postgres
sudo apt autoremove -y
Then install
sudo apt-get install postgresql postgresql-contrib
Check
pg_isready
Should be / var / run / postgresql: 5432