题解 | #牛客的课程订单分析(五)#

select yi.user_id,first_buy_date,second_buy_date,yi.cnt
from
    
 (select user_id,date first_buy_date,cnt
    from (
select user_id,date,cnt,rank()over(partition by user_id order by date) rk
from
(
    select *, count(*)over(partition by user_id) cnt
from order_info
where date>'2025-10-15'
and product_name in ('C++','Java','Python')
and status='completed'
) t
where cnt>=2) m  
    where rk=1) yi
 ,   
 (select user_id,date second_buy_date,cnt
    from (
select user_id,date,cnt,rank()over(partition by user_id order by date) rk
from
(
    select *, count(*)over(partition by user_id) cnt
from order_info
where date>'2025-10-15'
and product_name in ('C++','Java','Python')
and status='completed'
) t
where cnt>=2) m  
    where rk=2) er 

where yi.user_id=er.user_id

order by user_id