sql：查询每个用户每天最近的评分

WITH ranked_ratings AS (
    SELECT 
        user_id,
        rating,
        rating_date,
        ROW_NUMBER() OVER (
            PARTITION BY user_id, DATE(rating_date) 
            ORDER BY rating_date DESC
        ) AS rn
    FROM ratings
)
SELECT 
    user_id,
    rating,
    rating_date,
    DATE(rating_date) AS rating_day
FROM ranked_ratings
WHERE rn = 1;