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.dombrow...@gmail.com> wrote: > From: Brent Dombrowski <brent.dombrow...@gmail.com> > Subject: Re: [SQL] Dates and NULL's` > To: "John Fabiani" <jo...@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 > > > > -- > > Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) > > To make changes to your subscription: > > http://www.postgresql.org/mailpref/pgsql-sql > > > The NULLs will not be included. NULL matches nothing, not > even itself. > > Brent D. > > > -- > Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-sql > -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
