text: SELECT
  	dish_stuff.name,
  	string_agg(stuff, ','),
  	sum(g),
  	sum(calories),
  	sum(g / 100.0 * calories) AS result
  FROM dish_stuff JOIN stuff_calories
  ON dish_stuff.stuff = stuff_calories.name
  WHERE dish_stuff.name = '华夫饼'
  GROUP BY dish_stuff.name
  