明确题意:请统计各个城市在2021年10月期间,单日中最大的同时等车人数问题分解:计算等车人数变动情况:增加(select city,event_time uv_time,1 wait_uv from tb_get_car_record) union all减少(select city,coalesce(start_time,finish_time,end_time) uv_time,-1 wait_uv from tb_get_car_record tgcr join tb_get_car_order tgco on tgcr.order_id = tgco.order_id)筛选2021年...