题解 | 牛客的课程订单分析(五)

with a as
(select user_id,date,row_number()over(partition by user_id order by date) as rk,
count(*)over(partition by user_id) as cnt
from order_info
where status='completed' and date>'2025-10-15'
and product_name in('C++','Java','Python')),
b as (
select user_id,date as first_buy_date,cnt
from a
where rk=1 and cnt>=2),
c as (
select user_id,date as second_buy_date,cnt
from a
where rk=2 and cnt>=2)
select b.user_id,first_buy_date,second_buy_date,b.cnt
from b join c using(user_id)
order by b.user_id