From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Daniel Verite <daniel@manitou-mail.org>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: insensitive collations
Date: Sun, 6 Jan 2019 02:06:40 +0100
Message-ID: <a57e4005-00a6-66cb-c2a1-c98c019f3de2@2ndquadrant.com> (raw)
In-Reply-To: <eab7bd7b-7b2b-47f6-85b9-493e9d8cd834@manitou-mail.org>
References: <eab7bd7b-7b2b-47f6-85b9-493e9d8cd834@manitou-mail.org>
On 04/01/2019 17:05, Daniel Verite wrote:
> When using GROUP BY and ORDER BY on a field with a non-deterministic
> collation, this pops out:
>
> CREATE COLLATION myfr (locale='fr-u-ks-level1',
> provider='icu', deterministic=false);
>
> =# select n from (values ('été' collate "myfr"), ('ete')) x(n)
> group by 1 order by 1 ;
> n
> -----
> ete
> (1 row)
>
> =# select n from (values ('été' collate "myfr"), ('ete')) x(n)
> group by 1 order by 1 desc;
> n
> -----
> été
> (1 row)
I don't see anything wrong here. The collation says that both values
are equal, so which one is returned is implementation-dependent.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: peter.eisentraut@2ndquadrant.com, daniel@manitou-mail.org
Subject: Re: insensitive collations
In-Reply-To: <a57e4005-00a6-66cb-c2a1-c98c019f3de2@2ndquadrant.com>
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