A great visual explanation of SQL joins on Coding Horror, a...
Note: This article was originally published at Planet PHP
on 6 January 2011.
A great visual explanation of SQL joins on Coding Horror, a rewrite of Lig's awesome post: a€oGettinga€¯ Joins
Before you think about sending an email a€ohey, can you optimize my querya€¯, please read this article and make sure you're using your joins as expected.
Also, yay Venn diagrams!