Re: is any reason why only one columns subselect are allowed in array()? - Mailing list pgsql-hackers

From David Fetter
Subject Re: is any reason why only one columns subselect are allowed in array()?
Date
Msg-id 20081118153744.GC24041@fetter.org
Whole thread Raw
In response to Re: is any reason why only one columns subselect are allowed in array()?  ("Robert Haas" <robertmhaas@gmail.com>)
Responses Re: is any reason why only one columns subselect are allowed in array()?  (Sam Mason <sam@samason.me.uk>)
Re: is any reason why only one columns subselect are allowed in array()?  ("Pavel Stehule" <pavel.stehule@gmail.com>)
List pgsql-hackers
On Tue, Nov 18, 2008 at 10:29:53AM -0500, Robert Haas wrote:
> On Tue, Nov 18, 2008 at 10:06 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
> > Hello
> >
> > I am thinking about allowing 2D array from multicolumn subselect
> > (all columns have to share same type, ofcourse). Is there some
> > real limit, why this functionality is disallowed?
> 
> Seems like you could just write SELECT ARRAY[col1, col2, col3]
> instead of SELECT col1, col2, col3.

If I understand this right, Pavel is thinking that
   ARRAY(SELECT col1, col2, col3...)

should produce an array each element of which is the compound type
consisting of (col1, col2, col3), and if it doesn't produce one, we're
looking at a pretty large POLA violation.

Cheers,
David.
-- 
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: TABLE command
Next
From: Tom Lane
Date:
Subject: Re: Re: toast by chunk-end (was Re: PG_PAGE_LAYOUT_VERSION 5 - time for change)