I would like to have this function return as an array which contains all ID (integer) from this query, but i am stuck here:
CREATE OR REPLACE FUNCTION public.all_id(
prm_id integer)
RETURNS SETOF integer
LANGUAGE 'plpgsql'
COST 100.0
AS $function$
DECLARE
all_id integer;
-- all_id integer[]; gives an error, while integer only returns last value
BEGIN
SELECT id
COLLECT INTO all_id
FROM subject_data
WHERE sab_subject = (
SELECT sab_subject
FROM subject_data
WHERE id = prm_id
);
RETURN NEXT all_id;
END;
$function$;
SELECT * FROM public.all_id(1);
returns int[]instead. Also: there is no need for PL/pgSQL for this. A simple SQL function will do just fine.SELECT array_agg(id) FROM subject_data WHERE sab_subject = ( SELECT sab_subject FROM subject_data WHERE id = PRM_ID_VALUE )