The article says not to use Venn diagrams when explaining joins – that is, conveying the concepts to someone who doesn't already understand them.
You dismiss that as "silly" because anyone who already "grasps the basic principle" could figure it out. You're talking about the use of Venn diagrams by people who already "know how SQL joins basically work".
It sounds like you missed the point the article was making.
You dismiss that as "silly" because anyone who already "grasps the basic principle" could figure it out. You're talking about the use of Venn diagrams by people who already "know how SQL joins basically work".
It sounds like you missed the point the article was making.