题解 | #某乎问答最大连续回答问题天数大于等于3天#

本组最后一道题，打个卡，有两三天没做题了，就牛客自己出的题最离谱。这个题应该没有谁不会，打卡题

（用户最大连续天数，题目中没有对显示的days_cnt做具体说明，如果取用户连续最大，你自己再套一层）

select
    c.author_id,d.author_level,c.days_cnt
from 
(
    select
        b.author_id,count(distinct b.answer_date) as days_cnt
    from 
    (
        select 
            a.author_id,a.answer_date,date_sub(a.answer_date, interval (dense_rank() over(partition by a.author_id order by a.answer_date)) day) as groupDate
        from answer_tb a
    ) b group by b.author_id,b.groupDate having count(distinct b.answer_date) >= 3
) c join author_tb d on c.author_id = d.author_id
order by c.author_id