title: Isn't SQL A left join B, just A?
body: <p>So I was looking at a few graphs to understand the difference between the joins, and I came across this image:</p>
  
  <p><a href="https://i.stack.imgur.com/4zjxm.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4zjxm.png" alt="enter image description here"></a></p>
  
  <p>Maybe the problem is in representing this with Venn Diagrams. But looking at the first join, top left, isn't that basically just A? What difference does B make there?</p>
  
  <p>EDIT: <a href="https://blog.jooq.org/2016/07/05/say-no-to-venn-diagrams-when-explaining-joins/" rel="noreferrer">https://blog.jooq.org/2016/07/05/say-no-to-venn-diagrams-when-explaining-joins/</a></p>
  
  <p>This website explains it well</p>