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Using NULL in Advanced Search
buah:
EDIT: The original name of this topic was Funny Thing, as I can remember. Obviously the things became more serious here ;)
Funny thing.
Filters -> Viewed = 2533
1. + Advanced search->rating IS NULL =1817, or
2. + Advanced search->rating=0 =1817, or
3. + Advanced search->rating IS NOT NULL =2533?
Heh? :D
And I thought I learned something about logic
rick.ca:
Did this not help?
--- Quote from: rick.ca on February 09, 2010, 09:59:56 pm ---
--- Quote ---NULL Fields are always treated a bit differently by the database engine.
--- End quote ---
See Expressions Involving NULL in this reference. I've found the tip of thinking of NULL as UNKNOWN particularly helpful.
--- End quote ---
buah:
--- Quote from: rick.ca on March 04, 2010, 07:47:58 pm ---Did this not help?
--- Quote from: rick.ca on February 09, 2010, 09:59:56 pm ---
--- Quote ---NULL Fields are always treated a bit differently by the database engine.
--- End quote ---
See Expressions Involving NULL in this reference. I've found the tip of thinking of NULL as UNKNOWN particularly helpful.
--- End quote ---
--- End quote ---
I thought so Rick. But when it says that all 2533 is not uknown (IS NOT NULL) and at the same time that of those 2533, 1817 is uknown (IS NULL) I don't know what to think anymore...
rick.ca:
If IS NOT NULL is obtained by NOT-ing IS NULL and NULL means "unknown," then NULL might be expected to identify empty fields, but it's meaning is still unknown, so NOT-ing the result quite obviously doesn't exclude them, and now everything IS NOT NULL...
You might find it easier to do a simple search for Rating = 0. ;D
buah:
--- Quote from: rick.ca on March 05, 2010, 12:26:13 am ---You might find it easier to do a simple search for Rating = 0. ;D
--- End quote ---
It's getting harder thant to import 6000 movies ;)
When I do search rating=0, for the results I got also entries which rating field is empty, not 0? That's how all began, look at my first post
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