Great article, great topic. I belong to the newcomer group and as such I would have liked to see how those rules you talk about, were executed. You move the "where" into the join, but in the end you just mention some rules that puts the Cherry on top of it - and I don't understand what you did.

As a newcomer to the optimizer it is not all clear that the symbols in the execution plan mean table scans or Cartesian products. I can see they cost a lot but not what they in are (well, actually I can but ... I had to think first!). Maybe some kind of symbol explanation could be added? .. or maybe this is found elsewhere in some of the many links you added.

(and I now find that most questions was found on page two in some of the newest posts)