Question

我正在处理已导入MySql的GTFS数据集，我正在使用PHP访问它。我正在尝试查找给定时间和日期的特定路线的旅行。我的Sql查询看起来像这样

'SELECT  t.route_id AS route_id, t.service_id AS service_id, t.trip_headsign AS trip_headsign,
                t.trip_id AS trip_id,
              ( SELECT   departure_time
                FROM     stop_times
                WHERE    trip_id = t.trip_id
                ORDER BY departure_time ASC limit 1) AS initial_departure_time,
              ( SELECT   arrival_time
                FROM     stop_times
                WHERE    trip_id = t.trip_id
                ORDER BY arrival_time DESC limit 1) AS final_arrival_time
        FROM trips AS t INNER JOIN calendar_dates AS c
        WHERE t.service_id = c.service_id
          AND c.date ='.$calendar_date.' 
          AND initial_departure_time <='.$time.'
          AND'.$time. '<=final_arrival_time
          AND t.route_id ='.$route.'
        ORDER BY trip_id ASC';

$route，$calendar_date和$time都被传入。

查询返回的列未找到：

1054“ where子句”中的未知列“ initial_departure_time”。我认为initial_departure_time无法评估。

我也完全迷失了解决方法。任何线索，请先谢谢

Answer 1

您不能在WHERE子句中使用别名。

将子查询合并到WHERE子句中：

'SELECT t.route_id AS route_id, 
        t.service_id AS service_id, 
        t.trip_headsign AS trip_headsign,
        t.trip_id AS trip_id,
        (SELECT departure_time
         FROM stop_times
         WHERE trip_id = t.trip_id
         ORDER BY departure_time ASC limit 1) AS initial_departure_time,
        (SELECT arrival_time
         FROM stop_times
         WHERE trip_id = t.trip_id
         ORDER BY arrival_time DESC limit 1) AS final_arrival_time
FROM trips AS t INNER JOIN calendar_dates AS c
WHERE t.service_id = c.service_id
AND c.date ='.$calendar_date.' 
AND (SELECT departure_time
     FROM stop_times
     WHERE trip_id = t.trip_id
     ORDER BY departure_time ASC limit 1) <='.$time.'
AND'.$time. '<= (SELECT arrival_time
                 FROM stop_times
                 WHERE trip_id = t.trip_id
                 ORDER BY arrival_time DESC limit 1)
AND t.route_id ='.$route.'
ORDER BY trip_id ASC';

或者包装查询，然后在其中使用别名：

'SELECT * FROM (
        SELECT t.route_id AS route_id, 
        t.service_id AS service_id, 
        t.trip_headsign AS trip_headsign,
        t.trip_id AS trip_id,
        (SELECT departure_time
         FROM stop_times
         WHERE trip_id = t.trip_id
         ORDER BY departure_time ASC limit 1) AS initial_departure_time,
        (SELECT arrival_time
         FROM stop_times
         WHERE trip_id = t.trip_id
         ORDER BY arrival_time DESC limit 1) AS final_arrival_time
         FROM trips AS t INNER JOIN calendar_dates AS c
         WHERE t.service_id = c.service_id
         AND c.date ='.$calendar_date.' 
         AND t.route_id ='.$route.'
         ORDER BY trip_id ASC) a 
WHERE a.initial_departure_time <='.$time.'
AND'.$time. '<= a.final_arrival_time';

这可能会加快速度（您可能需要交换MIN和MAX）：

'SELECT t.route_id AS route_id, 
        t.service_id AS service_id, 
        t.trip_headsign AS trip_headsign,
        t.trip_id AS trip_id,
        MIN(s.departure_time) AS initial_departure_time,
        MAX(s.arrival_time) AS final_arrival_time
FROM trips AS t 
INNER JOIN calendar_dates AS c ON t.service_id = c.service_id
LEFT JOIN stop_times s ON s.trip_id = t.trip_id
WHERE c.date ='.$calendar_date.' 
AND t.route_id ='.$route.'
GROUP BY t.route_id, t.service_id, t.trip_headsign, t.trip_id,
HAVING '.$time.' BETWEEN MAX(s.arrival_time) AND MIN(s.departure_time)
ORDER BY trip_id ASC';

找不到GTFS MySQL查询栏

1 个答案: