题解 | 查询订单

SELECT
    o.order_id,
    c.customer_name,
    o.order_date
FROM
    orders AS o
    INNER JOIN
    customers AS c ON o.customer_id=c.customer_id
WHERE
    o.order_date IN (
        SELECT
            MAX(order_date)
        FROM
            orders
        GROUP BY
            customer_id
    )
ORDER BY
    c.customer_name;