Using NULL in Advanced Search

[buah]

Topic? What topic? Good grief, why is there never a moderator when you need one?

When there's no cat, mice rule the game

If PVD was designed to start rating form 1, I assure you I'd apply Asearch "Rating<1" for getting unrated movies. I would never think of NULL, and I'd still live in ignorance, blessed it was!

Was it worthy to repeat it?

[mgpw4me@yahoo.com]

Topic?  We don't need no topic !!  We already have said everything that needs saying.

[mgpw4me@yahoo.com]

See how my comprehension of NULL is more suitable?

Life IS NOT NULL = not (not aware of it)...

Your are too cool 

[buah]

Actually, that's what I heard about you, Canadians. Confirmed, so far.

[rick.ca]

Now that explains why he watches so many bad movies! For six months a year, he can make himself NULL by going outside in his underwear for 30 seconds. I, on the other hand, am torn between movies and strolling on the beach pretty much year round.

[mgpw4me@yahoo.com]

I may have to update my movie rating system.  Sex, Violence, Language = 3 star movie....

[AimHere]

This is the only behavior that would really make sense to me, and I suspect, the majority of users.

You've got to be kidding! The majority of users aren't even aware of the issue or haven't found a reason to care. Most of the rest are confused because the technical operation of the NULL operator does not yield a result that is intuitive in the circumstances. It's the lack of consideration of what is sensible to the average non-technical user that is the source of the problem in the first place.

I suppose so. I'm only saying "if it were up to me"...

And the conditions "IS NULL" and "= 0" should NOT be equivalent. A value  of zero is still a value, not a "null". Then "null/not null" would have NO relation to "zero" (or any other value) other than the obvious (i.e. if the field contains "zero", then it is NOT "null").

This is technically correct, but doesn't have any bearing on the question at hand, until it's decided it should. I contend that it should not. As I've pointed out a number of times in a number of different ways, there's no reason why NULL and 0 should not be equivalent—if that is simpler and appropriate for the situation at hand. I'm not suggesting there's no circumstance in which different meanings would be appropriate—but they do seem difficult to find. For most users in most situations, they both mean the same thing, and any attempt to make a distinction therefore only causes unnecessary confusion.

I see your point.

And the various "Rating" fields should make a distinction between "blank/null/unrated" and "zero", instead of treating them as equivalent!

And this is the perfect illustration of my general point. There's absolutely no justification for the assertion there "should" be "zero" rating. As a rating scale, there's nothing wrong with it starting at 1. It is, in fact, far more sensible than what you suggest. Using stars alone, there's no practical way to distinguish between NULL and 0. And there's no reason to rate something 0 when you can just as easily decide 1 has the exact same meaning. It's also obvious most users will find it perfectly intuitive the way it is. With a 0 rating allowed, we'd be forever explaining the distinction between "0" and "unrated."

Also true enough.

I'd settle for having "IS NULL" versus "IS NOT NULL" testing return consistent, intuitive results regardless of which field is being tested.

Aimhere

[CAD]

There's absolutely no justification for the assertion there "should" be "zero" rating. As a rating scale, there's nothing wrong with it starting at 1. It is, in fact, far more sensible than what you suggest. Using stars alone, there's no practical way to distinguish between NULL and 0. And there's no reason to rate something 0 when you can just as easily decide 1 has the exact same meaning. It's also obvious most users will find it perfectly intuitive the way it is. With a 0 rating allowed, we'd be forever explaining the distinction between "0" and "unrated."

Code: [Select]

Enter Devil Advocate ModeThere is nothing wrong with having a rating scale starting at 0.
If a movie is a real stinker 0 is perfectly valid.

null and 0 are different.
0 is a value - by definition - the value between + and - numbers
null is not populated. ie the field in question is empty. ( an invisible character eg "space" is a value and does not meet "null" criteria ).

I can see merit in having a rating system starting at 0 and null.
eg.
a movie is a stinker would be 0.
I haven't given this movie a rating yet would be null
Both should be independently searchable.

Using stars alone, there's no practical way to distinguish between NULL and 0.

perhaps if the movie is unrated " there is no spoon " err - there are no stars (displayed).

Code: [Select]

Exit Devil Advocate Mode

[rick.ca]

True to the Devil's Advocate tradition, you've presented a classic one-star argument that helps us all accept the foregone conclusion the rating scale is fine the way it is.