根据列值获取值

Question

这是我的 table:

    idMission Event               Timestamp
    1         detectedBubbleOut 2018-05-26T12:53:43.000Z
    1         arrived               2018-05-26T13:58:57.000Z
    1         detectedInBuilding    2018-05-26T12:42:20.000Z
    1         detectedBubbleIn  2018-05-26T12:37:36.000Z
    1         detectedTimeOut       2018-05-26T12:52:17.000Z
    1         scanFulfilled     2018-05-26T12:41:26.000Z
    1         detectedBubbleIn  2018-05-26T12:37:22.000Z
    1         customerInteraction   2018-05-26T13:59:04.000Z
    1         scanFulfilled     2018-05-26T13:59:01.000Z
    1         delFulfilled      2018-05-26T12:48:30.000Z
    1         eventFulfilled        2018-05-26T12:48:30.000Z
    1         nextDelivery      2018-05-26T12:50:20.000Z
    1         customerInteraction   2018-05-26T12:48:18.000Z
    1         detectedOutBuilding   2018-05-26T12:49:21.000Z
    1         arrived               2018-05-26T12:40:09.000Z
    1         detectedTimeIn        2018-05-26T12:38:58.000Z
    2         nextDelivery          2018-05-27T12:50:20.000Z
    2         customerInteraction   2018-05-27T12:48:18.000Z
    2         detectedOutBuilding   2018-05-27T12:49:21.000Z
    2         arrived               2018-05-27T12:40:09.000Z
    2         detectedTimeIn        2018-05-27T12:38:58.000Z

有些事件与时间戳相关联，这是事件发生的时间。我专注于事件 "arrived" 和 "detectedTimeIn"，但事件 "detectedTimeIn" 并不总是可用，所以我使用 "arrived"。我想要的只是根据特定事件获取时间戳。如果事件 "detectedTimeIn" 存在，那么我将获取它的时间戳，如果它不存在，那么我将获取事件的时间戳 "arrived"。这是我到目前为止所取得的成就：

    select 
        event,
        stp."timestamp" as TimeIN
    from main_source_execevent_coop stp
    where event Coalesce('detectedTimeIn', 'arrived')

预期结果：

1         detectedTimeIn        2018-05-26T12:38:58.000Z
2         arrived               2018-05-27T12:40:09.000Z

但它不起作用我只获得： 1 检测时间在 2018-05-26T12:38:58.000Z

忽略 "arrived" 行。你有什么建议吗？

谢谢

Answer 1

如果您正在查看 "next" 或 "previous" 事件，请使用 lead()/lag():

select t.*
from (select stp.*,
             lag(event) over (order by timestamp) as prev_event
      from main_source_execevent_coop stp
     ) stp
where event = 'detectedTimeIn' or
      (event = 'arrived' and next_event is distinct from 'detectedTimeIn');

Answer 2

试试这个：

SELECT * FROM 
   (SELECT event,
    stp."timestamp" as TimeIN
FROM your_table
      WHERE event ='detectedTimeIn'
      LIMIT 1

    UNION ALL

    SELECT event,
    stp."timestamp" as TimeIN
FROM your_table
      WHERE event ='arrived'
      LIMIT 1) a
LIMIT 1

根据列值获取值

Grab value based on column value

sql

postgresql-10