I had forgotten a lot about the DB field, and since my company uses postgreSQL, I bought it in a hurry. After listening to it, I remembered the MySQL content I learned at school a few years ago. The advantage is that it seems like a warm-up lecture that is good for activating the brain in a short amount of time. The downside is that it is an introductory course, so some concepts like group by and others are given as 'assignments' and I have to study them on my own.