题解 | 牛客的课程订单分析(六)

select a.id,a.is_group_buy,
case when a.is_group_buy='yes' then null else c.name end cilent_name
from (
    select id, is_group_buy, client_id,
    count(*) over(partition by user_id) cnt
    from order_info
    where status='completed'
    and date > '2025-10-15'
    and product_name in ('C++','Java','Python')
) a
left join client c
on a.client_id=c.id
where a.cnt>1
order by a.id