If you think of it more like a null is an unknown. two unknowns can never be the same. they are unknown.
and a known date can never equal an UNknown date. if the unknown date is equal to a date, then it is known!!!!
my head hurts!!
Ted
--- On Tue, 5/10/11, Brent Dombrowski <brent.dombrowski@gmail.com> wrote:
> From: Brent Dombrowski <brent.dombrowski@gmail.com>
> Subject: Re: [SQL] Dates and NULL's`
> To: "John Fabiani" <johnf@jfcomputer.com>
> Cc: pgsql-sql@postgresql.org
> Date: Tuesday, May 10, 2011, 4:33 PM
> On May 10, 2011, at 9:48 AM, John
> Fabiani wrote:
>
> > Hi,
> > Maybe this is a dumb question but if I have a date
> field that contains a NULL
> > will it show up when I ask for a where date range for
> the same date field.
> >
> > Where mydate >= "2011/04/01"::date and mydate<=
> "2011/04/30"::date
> >
> > With the above where will the NULL's be selected????
> >
> > I ask because I was always told that a NULL matches
> everything and nothing!
> >
> > Johnf
> >
> > --
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>
>
> The NULLs will not be included. NULL matches nothing, not
> even itself.
>
> Brent D.
>
>
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