题解 | 查询订单

WITH 
t1 AS (
SELECT 
    a.order_id,
    b.customer_name,
    a.order_date,
    ROW_NUMBER() OVER(PARTITION BY b.customer_name ORDER BY a.order_date DESC) AS rk
FROM orders AS a
INNER JOIN customers AS b ON a.customer_id	= b.customer_id	
ORDER BY b.customer_name    
)

SELECT 
    order_id,
    customer_name,
    order_date
FROM t1
WHERE rk = 1
ORDER BY customer_name;