题解 | #连续两次作答试卷的最大时间窗#

-- 题意其实没有太说清楚,最大间隔天数是否+1,已经最大最小天数差是否加1,同时,做题如果重复做一道题,需要记入,不去重.

-- 逻辑不难,就是题意不明,全靠猜o(╥﹏╥)o

select

t.uid

# ,timestampdiff(day,t.start_time,le_start_time) days_window

,max(datediff(coalesce(le_start_time,t.start_time),t.start_time))+1 days_window

,round((max(datediff(coalesce(le_start_time,t.start_time),t.start_time))+1) *count(t1.exam_id)/(datediff(max(t.start_time),min(t.start_time))+1),2) avg_exam_cnt

from

(

select

uid

,id

,start_time

,lead(start_time,1)over(partition by uid order by start_time) le_start_time

from exam_record  

where uid in

(

select

uid

from exam_record 

where year(start_time)='2021'

group by uid

having count(distinct date(submit_time)) >=2

) 

) t left join exam_record t1 on t.id=t1.id

where year(t.start_time)='2021'

group by t.uid

order by days_window desc ,avg_exam_cnt desc