A great visual explanation of SQL joins on Coding Horror, a rewrite of Lig’s awesome post: “Getting” Joins
Before you think about sending an email “hey, can you optimize my query”, please read this article and make sure you’re using your joins as expected.
Also, yay Venn diagrams!
Seriously fire the devs, they are doing it wrong.
interesting. may have to look into this further. If you couldn’t tell by the name, it’s a sql injection testing tool that you can run on firefox.