I would not have minded a bit more explaination on the syntax, but that I work around. I would have liked some idea/example of how this is used though. Seems like an academic excercise?
I didn't get the impression that the author was trying to show off, and most of the comments are well founded, but I especially agree with the "answers were nebulous" comment. I can go look up syntax and new functions but it would be nice if the author would provide a follow-up with a few examples where this finely-tuned result set would save us time elsewhere.
A few years ago, I was trying to figure out how 9 combinations of activities, 9 "if this, then that" trials and all their combinations, caused certain events to happen in a help desk developed by a major company. Their engineers couldn't answer my questions as to why I was getting an odd result when certain actions were combined. I decided to hand-build a truth table to show each possible case (in between my regular job duties) and after a month was able to show that a certain sequence of events gave a "predictable" but undesirable result that no one had anticipated. I sent the tables to the engineers and they fixed the "bug" Since the possible results of a set of actions grow exponentially, if I had had this procedure I would have saved myself hours (days) of work! Thank you for the procedure - it's a great help so, absolutely, keep showing off!!!
I also declare myself ignorant, and read the article looking for a practical everyday application. Not that the article wasn't interesting and valid, it's just that you normally expect a general and pragmatic application for most articles you see on this site... That being said, I'm sure that anybody in this specific field would appreciate the article, and being able to use SQL to tackle this problem.
Probably the first thing to do is to learn more about what a Truth Table is: http://en.wikipedia.org/wiki/Truth_table The Wikipedia mentions that it is used in digital/electronic design as an alternative to logic gates or code, including the design of a bit adder. I remember building a 4 bit adder (or was it 2 bit?) in college using logic gates, and I can see how having a truth table could have been useful in debugging it (maybe having expresions for intermediate outputs). The Wikipedia article has links to a couple online truth table generators, in case you require generating such a table, and don't have a SQL server handy to run the code in the article...
