Re: adding "order by" to a "group by" query

Louis-David Mitterrand <vindex+lists-pgsql-sql(at)apartia(dot)org> schrieb:
>
> But if I append this
>
> order by pt.type_fr = 'comédien';
>
> I get this error:
>
> ERROR: column "pt.type_fr" must appear in the GROUP BY clause or be used in an aggregate function
>
> It seems I am using pt.type_fr in an aggregate function (array_accum()),
> yet I get the error.
>
> Is there a way to to have a certain pt.type_fr bubble up (or down) in my
> search?

You can use a subquery like my example:

test=*# select i, comma(t) from (select distinct i,t from foo) bar group by i;
i | comma
---+---------
1 | a, b, c
(1 row)

Time: 0.554 ms
test=*# select i, comma(t) from (select distinct i,t from foo order by t desc) bar group by i;
i | comma
---+---------
1 | c, b, a
(1 row)

(I'm using the comma-aggregat - function from
http://www.zigo.dhs.org/postgresql/#comma_aggregate)

Hope that helps.

Andreas
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