题解 | 推荐内容准确的用户平均评分

SELECT
	ROUND(AVG(score),3) AS avg_score
FROM user_action_tb
WHERE 
	user_id IN (
		SELECT DISTINCT user_id
        FROM recommend_tb rt
		JOIN user_action_tb uat ON rec_user = user_id
        WHERE rt.rec_info_l = uat.hobby_l
    )