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From:doug Date:September 19 2005 3:06pm
Subject:Re: Yet another null question
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Thanks Martijn - that is a clear explanation of the philosophy. I did not get it
from the examples and the manual.

Doug

On Mon, 19 Sep 2005, Martijn Tonies wrote:

> Hello Doug,
>
>
> > My question question from MySQL 4.0.22: is it okay that a null interger tests
> as
> > equal to any value. I am not sure the table structure matters but in case
> it is
[cut]>
> That's because NULL is NOT a value (not the logical "not" ;) ... It's a
> state.
>
> Any column can have two states: either NULL or NOT NULL.
>
> When a column is "not null" it can have values suitable for it's given
> domain
> (eg: all integer values).
>
> If there's no value (NULL), how can you compare it?
>
> Think of "NULL" as "unknown". Is 2 equal to "unknown"? I don't know, so
> the result is "unknown", hence, NULL.
>
>
> Hope this helps,
>
> With regards,
>
> Martijn Tonies
> Database Workbench - tool for InterBase, Firebird, MySQL, Oracle & MS SQL
> Server
> Upscene Productions
> http://www.upscene.com
> Database development questions? Check the forum!
> http://www.databasedevelopmentforum.com
>

_____
Douglas Denault
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doug@stripped
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Thread
Yet another null questiondoug19 Sep
  • Re: Yet another null questionRoger Baklund19 Sep
    • Re: Yet another null questiondoug19 Sep
      • Re: Yet another null questionJasper Bryant-Greene19 Sep
      • Re: Yet another null questionJoerg Bruehe20 Sep
        • Re: Yet another null questiondoug20 Sep
    • Re: Yet another null questiondoug19 Sep
  • Re: Yet another null questionMartijn Tonies19 Sep
    • Re: Yet another null questiondoug19 Sep