题解 | 牛客的课程订单分析(七)

select (case 
          when b.name is null then 'GroupBuy' else b.name
          end) as source,count(*) as cnt
from (select user_id,client_id,count(*) over(partition by user_id) as num
      from order_info
      where date > '2025-10-15' and status = 'completed' and product_name in ('C++','Java','Python')
      ) as a
      left join client b on a.client_id = b.id
where a.num >= 2
group by name
order by source