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Re: Creating a VIEW with a POINT column

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Jan Urbański <j(dot)urbanski(at)students(dot)mimuw(dot)edu(dot)pl>
Cc: Mark Mielke <mark(at)mark(dot)mielke(dot)cc>, Nick <nboutelier(at)hotmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Creating a VIEW with a POINT column
Date: 2008-06-26 02:19:41
Message-ID: 3158.1214446781@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
=?UTF-8?B?SmFuIFVyYmHFhHNraQ==?= <j(dot)urbanski(at)students(dot)mimuw(dot)edu(dot)pl> writes:
>> Tom Lane wrote:
>>> Type point has no btree opclass, no hash opclass, and not even an
>>> operator named "=" (it looks like the functionality is named ~=
>>> for some odd reason).  I'd be interested to hear either a proposal of
>>> a principled way to define DISTINCT, or a way to implement it that
>>> was better than comparing every element to every other element...

> The way I see it there's nothing wrong with the definition of DISTINCT 
> and for types that can't be compared there is no way of calculating 
> distinct values other than comparing every element to every other.

"for types that can't be compared"?  Do you not see the logical
disconnect in that sentence?

			regards, tom lane

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Next:From: Jan UrbańskiDate: 2008-06-26 02:26:19
Subject: Re: Creating a VIEW with a POINT column
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