题解 | 推荐内容准确的用户平均评分
推荐内容准确的用户平均评分
https://www.nowcoder.com/practice/2dcac73b647247f0aef0b261ed76b47e
group by 去重 with a as( select rec_user,rec_info_l from recommend_tb rt join user_action_tb uat on rt.rec_user = uat.user_id and rt.rec_info_l = uat.hobby_l group by rec_user,rec_info_l) select round(avg(u.score),3) as avg_score from user_action_tb u where u.user_id in (select rec_user from a) #不能直接in a.rec_user，IN后面需要跟一个值或子查询
