题解 | #各城市最大同时等车人数#
各城市最大同时等车人数
https://www.nowcoder.com/practice/f301eccab83c42ab8dab80f28a1eef98
select city,max(wait_uv)max_wait_uv
from (
select city,event_time,wait
,sum(wait)over(partition by city order by event_time,wait desc)wait_uv
from (
select city,event_time,1 as wait from tb_get_car_record
join tb_get_car_order using(order_id)
where year(event_time)=2021 and month(event_time)=10
union all
select city,start_time as event_time,-1 as wait from tb_get_car_record
join tb_get_car_order using(order_id)
where year(event_time)=2021 and month(event_time)=10
)a
)b
group by 1
order by 2,1
