题解 | 牛客的课程订单分析(七)

select
    case when c.name is null then 'GroupBuy'
        when c.name is not null then c.name
    end as source,
    count(*) as cnt
from
    (select
        *,
        count(*) over(partition by user_id) as counts
    from
        order_info
    where
    date > '2025-10-15' and status = 'completed' and product_name in ('C++','Java','Python')) a

left outer join

    client as c
on 
    a.client_id = c.id
where 
    a.counts >= 2
group by 
    source
order by 
    source