乘客数大于1的司机信息

明确题意：

统计每位司机所载的乘客数大于1的司机id，乘客数以及所在的城市名称。

问题拆解：

• 统计每个司机的乘客数，知识点：count() group by
• 选出乘客数大于1的司机ID和乘客数，知识点：having
• 关联司机数据表，得到司机的城市ID，知识点：join
• 关联城市表，得到司机所在城市名称，知识点：join

代码实现：

select order_info_tb.driver_id, count(passenger_id) as passenger_num, city_name
from order_info_tb
left join driver_tb using(driver_id)
left join city_tb using(city_id)
group by driver_id
having passenger_num>1