题解 | #牛客的课程订单分析(五)# 简单易懂的解法

with tmp as (
select user_id,date,rank() over (partition by user_id order by date) rk
from order_info
where date> '2025-10-15' and product_name in ('C++','Java','Python') and status='completed'
order by user_id)

select user_id,(select date from tmp where user_id=t.user_id and rk =1) as first_buy_date,
(select date from tmp where user_id=t.user_id and rk =2) as second_bug_date,
count(1) as cnt
from tmp t
group by user_id
having count(1)>=2
order by user_id