Re: wCTE behaviour

On Sat, Nov 13, 2010 at 05:23:34PM +0200, Marko Tiikkaja wrote:
> On 2010-11-13 5:08 PM +0200, Tom Lane wrote:
> >Marko Tiikkaja<marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi> writes:
> >>On 13 Nov 2010, at 15:41, David Fetter<david(at)fetter(dot)org> wrote:
> >>>Similarly, if a normal CTE called a data-changing function but
> >>>was nevertheless not referred to, it would still run.
> >
> >>Actually, it wouldn't.
> >
> >Indeed, and that was considered a feature when we did it. I think
> >that having wCTEs behave arbitrarily differently on this point
> >might be a bad idea.
>
> So these queries would behave differently?
>
> WITH t AS (DELETE FROM foo RETURNING *) SELECT 1 WHERE false;
>
> WITH t AS (DELETE FROM foo RETURNING *) SELECT 1 FROM t LIMIT 0;

No.

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
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