题解 | 查询订单

select
    order_id,
    customer_name,
    order_date
from
    (
        select
            o.order_id,
            c.customer_name,
            o.order_date,
            row_number() over (
                partition by
                    c.customer_name
                order by
                    o.order_date desc
            ) as rk
        from
            orders o
            left join customers c on o.customer_id = c.customer_id
    ) r
where
    rk = 1
order by
    customer_name;

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