Question

我有MySQL DB，巴士路线停止如下：

id | route_id | stop_name | stop_id| arrival_time | departure_time  | order
1  | 1        | Stop1     | 500002 | 00:00:00     | 14:20:00        | 2
2  | 1        | Stop2     | 502001 | 15:45:00     | 15:50:00        | 3
3  | 1        | Stop3     | 602001 | 16:38:00     | 16:43:00        | 4
4  | 1        | Stop4     | 600001 | 17:23:00     | 00:00:00        | 5
5  | 2        | Stop5     | 500002 | 00:00:00     | 12:40:00        | 2
6  | 2        | Stop6     | 502001 | 14:05:00     | 14:10:00        | 3
7  | 2        | Stop7     | 602001 | 14:58:00     | 15:03:00        | 4
8  | 2        | Stop8     | 600001 | 15:43:00     | 00:00:00        | 5

并希望获得有关start＆amp; amp;的信息停止按route_id分组。查询是

SELECT MIN(route_stops.order), MAX(route_stops.order), route_stops.route_id, route_stops.stop_name as departure ,latest.stop_name as arrival
FROM route_stops
JOIN (
  SELECT stop_name
  FROM route_stops rs
  WHERE **route_stops.route_id**=rs.route_id
  ORDER BY `order` DESC
  LIMIT 1
) latest
group by route_id

但遗憾的是有错误说＃1054 - 'where子句'中的未知列'route_stops.route_id'

如何将父字段传递给JOINed子查询？

我最初对查询的期望是：

route_id |from_stop_name|to_stop_name
1 | Stop1 | Stop4
2 | Stop5 | Stop8

更新：找到的解决方案适合我

SELECT rs.route_id, rs.stop_name,rs.stop_id, j.stop_name,j.stop_id
FROM route_stops rs
INNER JOIN (
select d1.*
from `route_stops` d1
left outer join route_stops d2
on (d1.route_id = d2.route_id and d1.`order` < d2.`order`)
where d2.route_id is null
order by route_id
) j on j.route_id=rs.route_id
group by rs.route_id

Mysql：将父字段传递给join子查询

0 个答案: