This question got me!

Well done muzahm

The set ansi-nulls off could off course be debated, but still, good question.

The first if I had no problem with, but the second one got me...

I learned a lot about nulls through Tao's explanation and examples. Thanks, clear, precise and to the point.

The matter on nulls can so easily lead to queries not returning expected results and if you are unaware of the implications don't even realize your query is not returning what you expect and the "bug" is left in the code.....