(self plug) for coursework on the read-only SQL side, you might want to give <a href="http:&#x2F;&#x2F;pgexercises.com" rel="nofollow">http:&#x2F;&#x2F;pgexercises.com</a> a try. I have ambitions to expand it to include arrays and json, but alas haven&#x27;t found the time so far...