题解 | #牛客的课程订单分析(七)#
牛客的课程订单分析(七)
http://www.nowcoder.com/practice/d6f4a37f966145da8900ba9edcc4c068
注意:在进行左连接时,左连接client表,order_info中的client_id=0 ,而右表client中没有,连接时自动清除.
select
case when is_group_buy='No' then c.nameelse 'GroupBuy'
end source,
count(a.num) as cnt
from
(select *,
count(id) over(partition by user_id) as num
from order_info
where datediff(date,'2025-10-15')>0
and status='completed'
and product_name in ('C++','Java','Python'))a
left join client c
on a.client_id=c.id
where a.num>1
group by source
order by source;
