题解 | #重点：窗口函数：查用户刷题日期和下一次刷题日期#

select
    a.`user_id`,
    a.`date`,
    a.`nextdate`
from
    (
        select
            `user_id`,
            `date`,
            (
                lead (`date`, 1) over (
                    partition by
                        `user_id`
                    order by
                        `date` asc
                )
            ) as `nextdate`
        from
            questions_pass_record
    ) as a
order by
    a.`user_id`,
    a.`date`