Question

我需要有关sql表的帮助。

该表包含以下列：

EventID，PersonID，EventType，EventTime（datetime）以及其他一些不太重要的列。

让我们说两个主要的事件类型是打开一扇门并关上一扇门。

我需要同一个人打开一扇门和关门之间的持续时间（以秒为单位），或者他打开一扇门并打开另一扇门。（这当然只允许打开门的顺序）

为了清楚，如果第1人开门，而第2人关门，则不应该从查询中返回任何行。

我希望它有效但不是必须的。

我正在使用2008 SQL微软服务器（SQLEXPRESS）

以下是表格的示例：

EventID | PersonID | EventType | EventDate                | PreviousDoor | CurrentDoor
   1    |    1     |    1      | 12/10/2010 12:00:01.024  |      0       |     23
   2    |    1     |    2      | 12/10/2010 12:05:40.758  |      23      |     0
   3    |    2     |    1      | 12/10/2010 12:12:05.347  |      0       |     12
   4    |    1     |    1      | 12/10/2010 12:50:12.142  |      0       |     23
   5    |    2     |    2      | 12/10/2010 13:00:06.468  |      12      |     23
   6    |    3     |    1      | 13/10/2010 13:00:06.468  |      0       |     23

EventType：1（已打开的门），2（已关闭的门）

结果应该是：

EventID | PersonID | EventType | EventDate                | SecondsDifference
   1    |    1     |    1      | 12/10/2010 12:00:01.024  | 339
   3    |    2     |    1      | 12/10/2010 12:12:05.347  | 2881

我真的可以帮助你们。

提前致谢。

Answer 1

我认为应该这样做：

    SELECT          p1.EventID,
                    p1.PersonID,
                    p1.EventType,
                    p1.EventDate,
                    DATEDIFF(SECOND, p1.EventDate, p2.EventDate) AS SecondsDifference
    FROM            [Event] p1
    LEFT JOIN       [Event] p2  --Left join to self returning only closed door events
    ON              p2.PersonID = p1.PersonID
    AND             p2.EventType = 2 -- Closed Door
    AND             p1.EventID < p2.EventID --We don't want to bring back events that happened before the next event
    WHERE           p2.EventID IS NOT NULL --We don't want to show any people that have not closed a door

Answer 2

尝试这样的事情：

select t1.EventID, t1.PersonID, t1.EventType, t1.EventDate, datediff(second, t1.EventDate, t2.EventDate) as 'SecondsDifference'
from [Event] t1
inner join [Event] t2 on t2.PersonID = t1.PersonID and t2.EventType = 2 and t2.PreviousDoor = t2.CurrentDoor and t2.EventID < t1.EventID
where t1.EventType = 1

Answer 3

使用ROW_NUMBER和PARTITION会有帮助吗？我不确定以下是否是合法的SQL语句，因此请将其视为半伪代码。

SELECT *, 
  ROW_NUMBER() OVER(PARTITION BY PersonID ORDER BY EventTime) AS RowNumber,
  datediff(seconds, t2.EventTime, t1.EventTime) AS SecondsDiff
FROM Events t1 
  INNER JOIN 
    SELECT *,
      ROW_NUMBER() OVER(PARTITION BY PersonID ORDER BY EventTime) AS RowNumber 
    From Events t2 
  ON t1.RowNumber + 1 = t2.RowNumber 
    AND t1.PersonID = t2.PersonID AND t1.EventType = 1 
    AND (t2.EventType = 1 OR t2.EventType = 2)

SQL查询的问题

3 个答案: