Re: Writeable CTEs and side effects

From: Jaime Casanova <jcasanov(at)systemguards(dot)com(dot)ec>
To: Marko Tiikkaja <marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Writeable CTEs and side effects
Date: 2009-10-07 21:16:20
Message-ID: 3073cc9b0910071416r1413fb55vc536cf98a2e5033f@mail.gmail.com
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On Wed, Oct 7, 2009 at 4:08 PM, Marko Tiikkaja
<marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi> wrote:
>
> 1)      WITH t AS
>        (UPDATE foo SET bar = bar+1 RETURNING *)
>        SELECT * FROM t LIMIT 1;
>
> What's problematic here is that only 1 row is read from the CTE, meaning
> also that only one row is updated which, at least how I see it, is not
> what we want.  The CTE should only store one row and return that after
> it has completely processed the UPDATE statement.
>

i'm talking from my ignorance... but AFAIU this should process the
whole UPDATE and then form a WorkTable with the results...
what the select reads from that results is another thing...

--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157

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