Re: [GENERAL] Are multiple array_aggs going to be in the same order? - Mailing list pgsql-general

On Sun, Apr 9, 2017 at 4:27 PM, Guyren Howe <guyren@gmail.com> wrote:
>
> If I do a SELECT with a GROUP_BY and multiple ARRAY_AGGs, will the ARRAY_AGGs be guaranteed to have entries in the
same(ie corresponding) order? 
>
> eg
>
> SELECT
> u.name,
> ARRAY_AGG(o.order_date) AS order_dates,
> ARRAY_AGG(o.order_total) AS order_totals
> FROM
> user u JOIN
> orders o USING (user_id)
> GROUP BY
> u.user_id


It is unsafe to rely on aggregation order unless specified -- you can
add ORDER BY to the aggregation clause.

merlin