Re: FIRST_VALUE argument must appear in group by?

[Guyren Howe <guyren@xxxxxxxxx>]

On May 16, 2016, at 20:48 , David G. Johnston <david.g.johnston@xxxxxxxxx> wrote:

On Monday, May 16, 2016, Guyren Howe <guyren@xxxxxxxxx> wrote:

I have this SELECT clause as part of a larger query:

FIRST_VALUE(drs.id) OVER (PARTITION BY drs.order_ID ORDER BY drs.position ASC) AS current_drs_id

Seems reasonable to me: group and sort the fields in this table and give me the first value.

But I get "column "drs.id" must appear in the GROUP BY clause or be used in an aggregate function".

Huh?

The larger query would help…

SELECT
  o.id,
  os.status AS status,
  o.status_updated_at,
  o.should_hold_at_airlines,
  (SELECT drs2.id FROM delivery_route_segments drs2 WHERE drs2.order_id = o.id AND NOT drs2.completed ORDER BY drs2.position LIMIT 1) AS current_drs_id,


FROM
  orders o JOIN
  order_statuses os ON (o.status = os.id) JOIN
  delivery_route_segments drs ON (drs.order_id = o.id) JOIN
  pick_up_addresses pua ON (pua.order_id = o.id)
GROUP BY
  o.id, os.status

I would prefer to do the subquery as a window function, both because that is cleaner to read and also because I believe it is likely to be more efficient.