From: Laurenz Albe <laurenz.albe@cybertec.at>
To: daniel.fredouille@gmail.com
To: pgsql-docs@lists.postgresql.org
Subject: Re: unnest multirange, returned order
Date: Tue, 03 Oct 2023 15:46:23 +0200
Message-ID: <2bad53942920d2e501661af4cd49d6644a22b801.camel@cybertec.at> (raw)
In-Reply-To: <169627213477.3727338.17653654241633692682@wrigleys.postgresql.org>
References: <169627213477.3727338.17653654241633692682@wrigleys.postgresql.org>
On Mon, 2023-10-02 at 18:42 +0000, PG Doc comments form wrote:
> Page: https://www.postgresql.org/docs/16/functions-range.html
>
> The doc says:
> * unnest ( anymultirange ) → setof anyrange
> * Expands a multirange into a set of ranges. The ranges are read out in
> storage order (ascending).
>
> What is storage order ?
>
> At first I thought that it was the order in which the different ranges are
> inserted in the internal data structure. However, the following sort of
> shows that it is not:
> ```
> postgres=# select unnest('{[1,4), [8,10)}'::int4multirange + '{[-5,-3)}' -
> '{[2,3)}') ;
> unnest
> ---------
> [-5,-3)
> [1,2)
> [3,4)
> [8,10)
> (4 lignes)
> ```
> Whatever I try, it always return in range order instead of "storage order".
I'd say that the storag order is the order in which PostgreSQL stores
multiranges internally:
SELECT '{[100,200),[-100,-50),[-1,2)}'::int4multirange;
int4multirange
═══════════════════════════════
{[-100,-50),[-1,2),[100,200)}
(1 row)
Yours,
Laurenz Albe
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Cc: laurenz.albe@cybertec.at, daniel.fredouille@gmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: unnest multirange, returned order
In-Reply-To: <2bad53942920d2e501661af4cd49d6644a22b801.camel@cybertec.at>
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