
Updated for the latest database management systems, this introductory guide will get you up and running with SQL quickly. Whether you need to write database applications, perform administrative tasks, or generate reports, Learning SQL, Second Edition, will help you easily master all the SQL fundamentals. Each chapter presents a self-contained lesson on a key SQL concept or technique, with numerous illustrations, annotated examples, and exercises to let you practice the skills you learn.
1. Book "Head First SQL: Your Brain on SQL - A Learner's Guide" by Lynn Beighley
2. Book "Learning SQL: Generate, Manipulate, and Retrieve Data" by Alan Beaulieu
3. "Learn SQL" course from Codecademy.
You can see the full recommendation here [1].
I can also recommend Learning SQL by Alan Beaulieu, which was recommended in some HN comment. After looking into various books, some of them Postgres specific, I found this one to be the best for learning from scratch.
For people who looked at this wanting to get going with using database systems (as opposed to creating them), I'd recommend:
Learning SQL by Alan Beaulieu
SQL Performance Explained by Markus Winand
SQL Cookbook by Anthony Molinaro
The three of these will take you up to a pretty useful level of SQL knowledge/understanding. The first two are fairly easy reading to boot.Or they could buy a book like Learning SQL. Or spend a weekend on Youtube.
