Re: R: R: complex custom aggregate function

On Mon, Feb 2, 2009 at 2:30 PM, Scara Maccai <m_lists(at)yahoo(dot)it> wrote:
> Paolo Saudin wrote:
>> I use a master table with a "fulldate" field and filled with sequential dates to
>> fill gaps when meteo data is missing.
>
> I'm sorry, I still don't get it: how can you be sure that postgresql won't call perl_sliding_mean with not-ordered timestamps-data? I don't mean only in case of holes.
>
> The "order by" as far as I know is usually done at the very end of the plan, so I don't think it can affect the order of the data passed to the function...

You need to make a subquery with the ORDER BY on it. Postgres won't
re-order an ORDER BY in a subquery to happen outside the outer query.

So something like

select perl_function(foo) from (select foo from table order by bar)

--
greg