这么写对么 求指教 ``` select distinct d.id from goods as g join trans as t on g.id = t.goods_id where g.weight < 50 group by g.id having sum(count) >20 ``` ``` select distinct m.music_name from follow as f left join music_likes as ml on f.follower_id = ml.user_id left join music as m on m.music_id = ml.music_id where f.user_id = 1 and m.music_id not in (select ml. music_id from music_likes as ml where ml.user_id = 1) order by m.music_name asc; ```