题解 | 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

with t1 as(
    select distinct answer_date, tb1.author_id,author_level
    from answer_tb tb1
    left join author_tb tb2
    on tb1.author_id = tb2.author_id
),
t2 as (
    select * ,row_number() over(partition by author_id order by answer_date) rn
    from t1
),
t3 as (
    select *,date_sub(date(answer_date),interval rn day) dt from t2   
)
select author_id,author_level, count(*) days_cnt from t3  
group by  author_id,author_level
having days_cnt>=3