题解 | #牛客的课程订单分析(七)#

SELECT
CASE
WHEN a.client_id=0 THEN 'GroupBuy'
ELSE (
SELECT client.name
FROM client
WHERE a.client_id=client.id
)
END
AS source,COUNT(a.client_id) AS cnt
FROM order_info AS a
/1.先找到符合条件的订单/
WHERE a.date>'2025-10-15' AND a.status='completed' AND a.product_name IN ('C++','Java','Python')
AND (
SELECT COUNT()
FROM order_info AS b
WHERE a.user_id=b.user_id AND b.date>'2025-10-15' AND b.status='completed' AND b.product_name IN ('C++','Java','Python')
)>=2
/*2.再按照客户端分组/
GROUP BY a.client_id
ORDER BY source