Re: function returning a merge of the same query executed X time

On 04/22/2015 06:14 AM, Marc-André Goderre wrote:
> Hi all,
> I'm having difficulties to create a function that should execute X time the same query and return their results as a single table.
> I tried this way but it don't work :
> Thanks to help.

See comments inline.
>
> create function cm_get_json_loop_info(
> IN profile integer,
> IN distance double precision DEFAULT 10,
> IN x_start double precision DEFAULT 0,
> IN y_start double precision DEFAULT 0,
> IN nbr integer default 1)
>
> returns setof json as
> $BODY$
> declare jsona json;
> BEGIN
> for json a i in 1.. nbr loop
^^^^^^^
Not your declared variable. Besides which if the variable
where correct you would just be assigning it the numbers 1 through nbr.

See:
http://www.postgresql.org/docs/9.4/interactive/plpgsql-control-structures.html#PLPGSQL-CONTROL-STRUCTURES-LOOPS

40.6.3.5. FOR (Integer Variant)

>
> select row_to_json(q)
> from (select row_number() over() as id, sum(cost) as total_cost,sum(length) as total_length,json_agg(row_to_json(r)) as data
> from (select * from cm_get_loop_route_4(2, 10, -73.597070, 45.544083))r)q
> return next jsona

The output of the query is not assigned to jsona.

http://www.postgresql.org/docs/9.4/interactive/plpgsql-statements.html#PLPGSQL-STATEMENTS-ASSIGNMENT

40.5.3. Executing a Query with a Single-row Result

> end loop;
> return jsona;

This should be just RETURN.

http://www.postgresql.org/docs/9.4/interactive/plpgsql-control-structures.html#PLPGSQL-STATEMENTS-RETURNING

40.6.1.2. RETURN NEXT and RETURN QUERY
>
> Marc
>
>
>

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