题解 | #牛客的课程订单分析(四)#
牛客的课程订单分析(四)
https://www.nowcoder.com/practice/c93d2079282f4943a3771ca6fd081c23
select user_id , date as first_buy_date, cnt from (
select user_id, date,
sum(case when status = 'completed' then 1 else 0 end) over (partition by user_id)as cnt,
dense_rank() over (partition by user_id order by date) as rn
from order_info
where product_name in ('C++','Java','Python') and date > '2025-10-15'
) t where t.rn = 1 and t.cnt>= 2 order by user_id
