题解 | 每天登陆最早的用户的内容喜好

select
    log_day,
    user_id,
    hobby
from
    (
        select
            date (log_time) log_day,
            user_id,
            dense_rank() over (
                partition by
                    date (log_time)
                order by
                    log_time
            ) r
        from
            login_tb
    ) t
    join user_action_tb using (user_id)
where
    r = 1;