题解 | #牛客的课程订单分析(七)#

select
ifnull(t3.name,'GroupBuy'),
count(*)
from 
(select t1.user_id,
t1.client_id
from
(
    select *,count(id) over(partition by user_id) as number,
    dense_rank()over(partition by user_id order by date) rt
    from order_info
    where datediff(date,"2025-10-15")>0
      and status ="completed"
      and product_name in ("C++","Java","Python")
) t1
where t1.number >1) t2
left join client t3
on t2.client_id=t3.id
group by 1
order by 1