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NULL


NULL

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honza.mf
honza.mf
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Sorry: NULL IS NULL.



See, understand, learn, try, use efficient
© Dr.Plch
Tao Klerks
Tao Klerks
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Hah, should have known Hugo would come explain everything properly - ignore my posts, concentrate on his Smile

http://poorsql.com for T-SQL formatting: free as in speech, free as in beer, free to run in SSMS or on your version control server - free however you want it.
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I got my point because I could guess the spirit of the question from the "UNKNOWN" option, but it's plain wrong.
NULL := NULL

--Gianluca Sartori

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Christian Buettner-167247
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Hugo Kornelis (4/13/2010)
[wrote lots of good stuff...]


Thanks for this excellent clarification which deserves an Article on its own! So you better get started! :-D

Best Regards,

Chris Büttner
Hugo Kornelis
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Christian Buettner-167247 (4/13/2010)
Hugo Kornelis (4/13/2010)
[wrote lots of good stuff...]


Thanks for this excellent clarification which deserves an Article on its own! So you better get started! :-D
Thanks, Chris!

I already wrote and published that article some years ago. Just not here, but on my blog. See the links in my first post.


Hugo Kornelis, SQL Server MVP
Visit my SQL Server blog: http://sqlblog.com/blogs/hugo_kornelis
Cath Trimble
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I opted for the NULL answer. My understanding was, and still is, that NULL doesn't mean unknown, but that any potential value is simply not there.

Regards,
Cath

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Niko Neugebauer
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For me, NULL is definitely not «Unknown», since «Unknown» is a result of a logical operation.
Being in doubt i voted for NULL, but the question should have had more explanation.
Conan The Canadian
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NULL means the absense of a value....

NULL means NULL.

NULL does not equal NULL which is very different statement from means.

Kev -=Conan The Canadian=-
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honza.mf
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And what about not mentioned option "empty value". For numerics it is clear, but for strings, it's dangerous to mix with empty string.
NULL is unassigned value - no value at all, UKNOWN is special logical value, and zero/'' are normal values.



See, understand, learn, try, use efficient
© Dr.Plch
Nadrek
Nadrek
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For a question about NULL to make any sense, the context and/or the operational definition must be set.

NULL has different results in the same operations based on other settings, therefore, NULL has different definitions based on those settings.

None of that is counting certain segments of actual practice, (not theory) in which the operational definition of NULL is actually 'Treat it as you treat empty string or 0 or some other known value, because those who came before failed to set the column to be NOT NULL for one or more reasons, and we aren't allowed to change the data or the setting now'.
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