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
asingle 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.klaver@aklaver.com