题解 | 某乎问答最大连续回答问题天数大于等于3天的用户及其对应等级

select 
    t1.author_id, t1.author_level, max(t1.rn) as days_cnt
from(
    select 
        an.author_id, au.author_level, an.answer_date, 
        dense_rank()over(partition by an.author_id order by an.answer_date) as rn 
    from 
        answer_tb an join author_tb au 
    on 
        an.author_id = au.author_id
)t1
where t1.rn >= 3
group by 
	author_id, author_level