Re: sql function with empty row

On 05/16/2018 11:07 AM, Philipp Kraus wrote:
> Hello,
>
> I have defined a SQL function
>
> CREATE OR REPLACE FUNCTION substancetrivialname(text)
> RETURNS substance
> LANGUAGE 'sql'
> COST 100
> VOLATILE
> AS $BODY$
> select s.* from substancetrivialname n
> join substance s on s.id = n.idsubstance
> where lower(btrim(n.name)) = lower(btrim($1));
> $BODY$;
>
> substance and substancetrivialname have got a 1-to-N relationship (for each substance can exist multiple trivial names).
> If I call the function with a non-existing trivial name it returns a single row with all fields are set to NULL.

Well I was on the right track for the wrong reason. At any rate SETOF works:

select * from cell_per where cell_per = 100;
line_id | category | cell_per | ts_insert | ts_update | user_insert |
user_update | plant_type | season | short_category
---------+----------+----------+-----------+-----------+-------------+-------------+------------+--------+----------------
(0 rows)

CREATE OR REPLACE FUNCTION cp(integer)
RETURNS cell_per
LANGUAGE 'sql'
AS $BODY$
select cell_per.* from cell_per where cell_per = $1;
$BODY$;

select * from cp(100);
line_id | category | cell_per | ts_insert | ts_update | user_insert |
user_update | plant_type | season | short_category
---------+----------+----------+-----------+-----------+-------------+-------------+------------+--------+----------------
NULL | NULL | NULL | NULL | NULL | NULL |
NULL | NULL | NULL | NULL
(1 row)

CREATE OR REPLACE FUNCTION cp(integer)
RETURNS SETOF cell_per
LANGUAGE 'sql'
AS $BODY$
select cell_per.* from cell_per where cell_per = $1;
$BODY$;

select * from cp(100);
line_id | category | cell_per | ts_insert | ts_update | user_insert |
user_update | plant_type | season | short_category
---------+----------+----------+-----------+-----------+-------------+-------------+------------+--------+----------------
(0 rows)

> If I run the join query directly it returns an empty record set on a non-existing trivial name.
> I expected equal behavior on my function, so my question is, how can I fix this?
>
> Thanks
>
> Phil
>
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com