题解 | 查询出每个运输方式在不同城市的平均运输时长以及总运输费用

select distinct destination_city
,transport_name
,round(avg(datediff(delivery_date,order_date)) over(partition by destination_city,transport_name),2) as average_transport_duration
, round(sum(total_cost) over(partition by destination_city,transport_name),2) as total_transport_cost
from transport_detail t
join order_info o on t.transport_id = o.transport_id
join cost_data c on o.order_id = c.order_id
order by destination_city
,transport_name