题解 | #牛客的课程订单分析(五)#

select
user_id
,date first_buy_day
,second_day
,cnt
from
(
    select
    *
    ,row_number()over(partition by user_id order by date) rank1
    ,lead(date,1)over(partition by user_id order by date) second_day
    ,count(*)over(partition by user_id) cnt
    from order_info
    where date > '2025-10-15'
    and status = 'completed'
    and product_name in ('C++','Java','Python')
)table1
where rank1 = 1
and second_day is not null
order by 1