[nycphp-talk] Need help understanding NULL

Matt Juszczak matt at
Sat Aug 29 16:10:55 EDT 2009


This might potentially be wrong, but what I think of NULL is this. If 
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.

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.

Sort of how I use it sometimes, and MAY BE WRONG.  So I would listen to 
what others have to say =)

On Sat, 29 Aug 2009, lists at wrote:

> I don't usually use NULL values for anything because no matter how much
> I read I can't figure out the purpose of it. So far this hasn't been a
> problem for me, but I figure it's going to trip me up sooner or later.
> I've read the NULL sections of the PHP & MySQL manuals and even tried
> googling for articles, but the concept of a ?a missing unknown value?
> makes my brain hurt. Can someone please, please, please attempt to
> explain--in the simplest terms possible--what the practical
> advantages/disadvantages of using it might be?
> Regards,
> Bev
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