Re: ERROR: FULL JOIN is only supported with merge-joinable

From: Greg Stark <gsstark(at)mit(dot)edu>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Harco de Hilster <Harco(dot)de(dot)Hilster(at)ATConsultancy(dot)nl>, pgsql-general(at)postgresql(dot)org
Subject: Re: ERROR: FULL JOIN is only supported with merge-joinable
Date: 2006-03-13 20:16:35
Message-ID: 87r756je1o.fsf@stark.xeocode.com
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Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Harco de Hilster <Harco(dot)de(dot)Hilster(at)ATConsultancy(dot)nl> writes:
> > What is the definition of a merge-joinable condition?
>
> Equality on a sortable datatype.
>
> > Can I create an type/operator that compares both records that is
> > considered merge-joinable?
>
> I think you could do something involving a time interval datatype that
> considers "overlap" as equality and does something reasonable for
> sorting non-overlapping intervals.

How could a non-transitive property ever be merge joinable though?

--
greg

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