[nycphp-talk] Need help understanding NULL

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Sat Aug 29 16:26:40 EDT 2009

Matt Juszczak wrote:
> something is NULL, then you don't know what it is.  It could be empty,
> or it could be set.  You just don't know.

That's precise the part I can't seem to wrap my head around.

> If something is empty, then you know it's empty.  So if birthdate is set
> to '', then you know they have no birthdate.  But if it's set to NULL,
> you don't know if they have one or not.

Thanks for trying, Matt, but I still don't get the purpose of "knowing
that you don't know" something, so to speak.



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