Database: is better mySQL or PostgreSQL

Hello! What do you think is better to learn? I never did back end, I am about to learn databases, which should I know on your experience? which of these 2 are more in demand?

They are both extensively used. You won’t go wrong using either, but ime Postgres is generally considered the better of the two (by quite a long way in some regards). However, for what you want to do (learn basics), it’s likely to make almost no difference whatsoever which one you pick.

Also note there are some umm licensing issues with MySQL due to it being owned by Oracle that you may not care about . But if you did you can just use MariaDB instead of MySQL as it is a fork of MySQL and hence works almost identically.