PostgreSQL function to find points in distance

gistfile1.txt

BEGIN;

CREATE OR REPLACE FUNCTION api.geog_points_in_distance(latitude NUMERIC, longitude NUMERIC, distance NUMERIC)
  RETURNS JSON
  SECURITY DEFINER
  LANGUAGE PLPGSQL STABLE
  SET search_path TO PUBLIC, api
  AS $$
DECLARE
  _lat        NUMERIC DEFAULT latitude::NUMERIC;
  _lng        NUMERIC DEFAULT longitude::NUMERIC;
  _distance   NUMERIC DEFAULT COALESCE(distance::NUMERIC, 500);
  result      JSONB;
BEGIN

  WITH geog_points AS (
    SELECT 
      gp.*
      , ST_Distance(gp.geog, ST_SetSRID(ST_MakePoint(_lng, _lat),4326)) AS distance_4326
    FROM api.geog_point AS gp
    WHERE ST_DWithin(gp.geog, ST_Point(_lng, _lat)::geography, _distance)
    ORDER BY gp.geog::geometry <-> ST_SetSRID(ST_MakePoint(_lng, _lat),4326)
  )
  SELECT
    json_agg(geog_points)
    FROM geog_points
    INTO result;

  RETURN result;
END $$;

GRANT EXECUTE ON FUNCTION api.geog_points_in_distance(latitude NUMERIC, longitude NUMERIC, distance NUMERIC) TO app_anonymous;

COMMIT;