@kenneth Fisher: Thx for the article, it's most certainly something that gets a lot of people confused and the given examples are a great help to show what's going on.
On top of that, the part
“Why is that! “ I hear some of you cry. The rest are split between 75% who already know the answer, 15% who don’t care, and the remaining 10% are still trying to figure out what an OUTER JOIN is and why I’m going on about it.
will have me smiling for the rest of the day =)
@celko: Although I understand the need to 'preach against bad design', IMHO you're picking the wrong fight here and most certainly could have used more respectful wording.