The author's diagrams aren't perfect either, but I think they are much more clear to novice coders about the real workings of joins. Check this out, similar to

The author's diagrams aren't perfect either, but I think they are much more clear to novice coders about the real workings of joins. Check this out, similar to the author's approach, but animated. This is the best visual of SQL joins I've ever found. https://news.ycombinator.com/item?id=16983007 https://news.ycombinator.com/item?id=16983007