题解 | 推荐内容准确的用户平均评分

with t as(#先把推荐正确用户找出来，并去重，以防同一个用户多次推荐正确
select 
    round(avg(score),3) avg_score
from recommend_tb rt inner join user_action_tb uat on rt.rec_user = uat.user_id and rt.rec_info_l = uat.hobby_l
group by uat.user_id
)
select 
    avg(avg_score) avg_score
from t