PostgreSQL：动态查询到JSON数组

Question

I would like to execute a dynamic query using the EXECUTE statement and put the result into a json array.

I am getting

SQL Error [22P02]: ERROR: malformed array literal: "[malformed array literal: "[{"id": "1"}]" Detail: "[" must introduce explicitly-specified array dimensions. Where: PL/pgSQL function ....

Here is what I have so far.

CREATE or replace function my_function()
returns json[] as $$
declare result json[];
begin
    execute '
        SELECT array_to_json(array_agg(t)) from (
            select ....
        ) t;
    ' into result;

    -- doing some stuff with the array

    return result;
END;
$$ language 'plpgsql';

Answer 1

As the user "a_horse_with_no_name" stated. array_to_json does return a json object and NOT a json array.

In my case i could achieve what i want using

CREATE or replace function my_function()
returns json as $$
declare result json;
begin
    execute '
        SELECT (''{ "data": '' || json_agg(t)::text || ''}'')::json from (
            select ....
        ) t;
    ' into result;

    -- doing some stuff with the array

    return result;
END;
$$ language 'plpgsql';