Search Postgresql Archives

Re: Why is NULL = unbounded for rangetypes?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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




-- 
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux