题解 | #牛客的课程订单分析(七)#

select IFNULL(c.`name`,'GroupBuy') source,count(*) cnt
from(
    select id,client_id,is_group_buy,count(*) over(partition by user_id) n
    from order_info
    where date>'2025-10-15'
    and `status`='completed'
    and product_name in('C++','Java','Python'))t left join client c
on t.client_id=c.id
where t.n>1
group by t.client_id
order by source