Re: Why is NULL = unbounded for rangetypes?
От | Jeff Davis |
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Тема | Re: Why is NULL = unbounded for rangetypes? |
Дата | |
Msg-id | 1373303775.30779.3.camel@jdavis обсуждение исходный текст |
Ответ на | Why is NULL = unbounded for rangetypes? (Andreas Joseph Krogh <andreak@officenet.no>) |
Ответы |
Re: Why is NULL = unbounded for rangetypes?
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Список | pgsql-general |
On Mon, 2013-07-08 at 10:19 +0200, Andreas Joseph Krogh wrote: > Hi. > > Both of these queries return TRUE because NULL means "unmounded": > select daterange('2013-07-01' :: DATE, null, '[]') && daterange('2013-07-04' :: DATE, '2013-07-30' :: DATE, '[]'); > select daterange(null, '2013-08-11' :: DATE, '[]') && daterange('2013-07-04' :: DATE, '2013-07-30' :: DATE, '[]'); > What is the rational behind this behavior of NULL? It's just a convenience that passing NULL to a constructor creates an unbounded range. The alternatives of having extra constructors for unbounded ranges were discussed, but seemed more awkward. Note that ranges do not allow either bound to be NULL. That would create a lot of semantic problems. Does that answer your question? Regards, Jeff Davis
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