sql - 获得两次SQL Server 2012之间的差异

背景：

我正在尝试确定客户在特定房间里停留的时间。每个客户都可以通过CustomerID进行标识，并且当他们访问时，会为其分配一个VisitNumber。例如，如果客户今天拜访，他们将得到的VisitNumber。然后，他们离开并下周返回，VisitNumber为111112。

当客户第一次访问时，最初没有为他们分配房间，而当最终为他们分配了指定的房间时，会将条目写入数据库。 CurrentRoom将为空，因为他们还没有房间，而NewRoom是他们已移入的房间。

该条目将被记录为事件1（客户从无房间移到另一房间），时间是交易发生的时间。如果客户随后在其现有逗留期间被转移，这将被记录为事件9（客户从一个房间转移到另一个房间），并且还将记录CurrentRoom和* NewRoom值。

问题

我已经使用LAG和LEAD设法获得了上一行的时间和下一行的时间，然后算出两次之间的差值，这使我得到了客户在该特定房间花费的时间长度。

使用LAG时，问题在于它正在获得先前的价值，在某些情况下，这可能是来自完全不同的客户的价值。我想只获取特定CustomerID和当前VisitNumber的LAG和LEAD值，然后计算出这两个值之间的差异，以找出该客户在一个房间里呆了多长时间。

演示数据：

CREATE TABLE #beds
(
    [id] [int] IDENTITY(1,1) NOT NULL PRIMARY KEY,
     [User] [nvarchar](50) NULL,
    [CustomerID] [nvarchar](50) NULL,
     [Area] [nchar](10) NULL,
    [Event] [nvarchar](50) NULL,
    [VisitNumber] [nvarchar](50) NULL,
    [Time] [datetime] NULL,
     [CurrentRoom] [nvarchar](50) NULL,
     [NewRoom] [nvarchar](50) NULL
)
GO

INSERT INTO #beds ([User],[CustomerID],[Area],[Event],[VisitNumber],[Time],[CurrentRoom],[NewRoom])
VALUES ('00001','C11111111','Area1',2,111111111,'2017-03-22 11:05:44.360','B22','B44'),
('00001','C11111111','Area1',1,111111111,'2017-03-22 11:05:15.517','','B22'),
('00001','C22222222','Area2',1,222222222,'2017-03-22 07:38:16.117','','POD3'),
('00001','C22222222','Area2',3,222222222,'2017-03-22 07:41:24.787','POD3','POD3'),
('00001','C22222222','Area2',9,222222222,'2017-03-22 09:10:49.697','POD3',''),
('00001','C22222222','Area2',1,222222222,'2017-03-22 10:05:19.130','','POD15'),
('00001','C22222222','Area2',2,222222222,'2017-03-22 10:13:43.057','POD15','A'),
('00001','C22222222','Area2',3,222222222,'2017-03-22 10:25:01.527','A','A'),
('00001','C22222222','Area2',3,222222222,'2017-03-22 10:46:03.960','A','A'),
('00001','C22222222','Area2',3,222222222,'2017-03-22 10:46:17.030','A','A'),
('00002','C33333333','Area3',1,333333333,'2017-03-22 09:20:23.660','','B46'),
('00001','C33333333','Area2',9,333333333,'2017-03-22 08:53:32.860','POD8','POD1'),
('00001','C33333333','Area2',1,333333333,'2017-03-22 07:34:58.810','POD7','POD8'),
('00001','C33333333','Area2',1,333333333,'2017-03-22 11:49:55.203','','BB4'),
('00001','C33333333','Area2',3,333333333,'2017-03-22 11:50:11.943','BB4','BB4'),
('00001','C33333333','Area2',3,333333333,'2017-03-22 08:42:56.157','POD8','POD8'),
('00001','C33333333','Area2',3,333333333,'2017-03-22 08:22:59.157','POD8','POD8'),
('00003','C33333333','Area3',1,333333333,'2017-03-23 06:41:12.753','','B46')

GO

这是我到目前为止的查询；这将为我提供上一行的值和下一行的值，但是我认为这并没有考虑到客户。

SELECT
    T1.[User], T1.[CustomerID],
    T1.[Area], T1.[Event],
    T1.[VisitNumber],
    T1.[CurrentRoom], T1.[NewRoom],
    T1.[Time],
    LAG(T1.TIME) OVER (ORDER BY T1.VisitNumber) PreviousTime,
    LEAD(T1.TIME) OVER (ORDER BY T1.VisitNumber) NextTime
FROM
    #beds t1
WHERE
    T1.[Area] = 'Area2'
    AND T1.[CurrentRoom] IS NOT NULL
    AND T1.[NewRoom] IS NOT NULL
    AND T1.[CustomerID] IS NOT NULL
    AND T1.[CustomerID] <> ' '
    AND T1.Event IN (1,9)
ORDER BY
    VisitNumber DESC

预期的输出：这是我期望的输出。我只想要TimeInRoom（时间中不包括日期字段）：

+------------+-------+-------------+-------------+---------+------------+
| CustomerID | Area  | VisitNumber | CurrentRoom | NewRoom | TimeInRoom |
+------------+-------+-------------+-------------+---------+------------+
|C33333333   |Area2  | 333333333   |             | BB4     | 00:10      |
|C33333333   |Area2  | 333333333   |             | POD8    | 00:20      |
|C33333333   |Area2  | 333333333   | POD8        |         | 00:30      |
+------------+-------+-------------+-------------+---------+------------+

最佳答案

我希望这有帮助：

;WITH cte_Result AS
(
    SELECT
        [CustomerID],
        [Area],
        [VisitNumber],
        [CurrentRoom],
        [NewRoom],
        [Time],
        LAG([TIME]) OVER (partition by [CustomerID],[VisitNumber] ORDER BY ID DESC) PreviousTime,
        LEAD([TIME]) OVER (partition by [CustomerID],[VisitNumber] ORDER BY ID DESC) NextTime
    FROM #beds
    WHERE   [Area] = 'Area2'
        AND [CurrentRoom] IS NOT NULL
        AND [NewRoom] IS NOT NULL
        AND [CustomerID] IS NOT NULL
        AND [CustomerID] <> ' '
        AND [Event] IN (1,9)
        --AND [CustomerID] = 'C33333333'
),
cte_BuildStayPeriod
AS (
    SELECT CustomerID,
        Area,
        VisitNumber,
        CurrentRoom,
        NewRoom,
        DATEDIFF(SECOND, COALESCE([NextTime], PreviousTime), COALESCE(PreviousTime, [time])) AS StayDuration
    FROM cte_Result
)
SELECT CustomerID,
    Area,
    VisitNumber,
    CurrentRoom,
    NewRoom,
    StayDuration,
    CAST(DATEADD(SECOND, StayDuration, '1900-01-01') AS TIME) AS StayDuration
FROM cte_BuildStayPeriod