sql - 如何在 SQL 中将顺序的、带时间戳的行组合在一起并返回每个组的日期范围

Question

我有一个 MS SQL 2008 数据库表，如下所示:
Registration | Date | DriverID | TrailerID
一些数据的示例如下:

AB53EDH,2013/07/03 10:00,54,23
AB53EDH,2013/07/03 10:01,54,23
...
AB53EDH,2013/07/03 10:45,54,23
AB53EDH,2013/07/03 10:46,54,NULL <-- Trailer changed
AB53EDH,2013/07/03 10:47,54,NULL
...
AB53EDH,2013/07/03 11:05,54,NULL
AB53EDH,2013/07/03 11:06,54,102  <-- Trailer changed
AB53EDH,2013/07/03 11:07,54,102
...
AB53EDH,2013/07/03 12:32,54,102
AB53EDH,2013/07/03 12:33,72,102  <-- Driver changed
AB53EDH,2013/07/03 12:34,72,102

如您所见，数据表示在任何时间点哪个司机和哪个拖车被附加到哪个注册。我想要做的是生成一个报告，其中包含驱动程序和拖车的每个组合处于事件状态的时间段。因此，对于上面的示例数据，我想生成如下所示的内容:

Registration,StartDate,EndDate,DriverID,TrailerID
AB53EDH,2013/07/03 10:00,2013/07/03 10:45,54,23
AB53EDH,2013/07/03 10:46,2013/07/03 11:05,54,NULL
AB53EDH,2013/07/03 11:06,2013/07/03 12:32,54,102
AB53EDH,2013/07/03 12:33,2013/07/03 12:34,72,102

您将如何通过 SQL 执行此操作？

更新:感谢到目前为止的答案。不幸的是，当我将其应用于我拥有的生产数据时，它们停止工作。迄今为止提交的查询在应用于部分数据时无法正常工作。

下面是一些示例查询，用于生成数据表并使用上面的虚拟数据填充它。这里的数据比上例中的多:驱动程序、拖车组合 54,23 和 54,NULL 已被重复，以确保查询识别出这是两个不同的组。我还使用不同的日期范围复制了相同的数据三次，以测试在部分数据集上运行时查询是否有效:

CREATE TABLE [dbo].[TempTable](
    [Registration] [nvarchar](50) NOT NULL,
    [Date] [datetime] NOT NULL,
    [DriverID] [int] NULL,
    [TrailerID] [int] NULL
)

INSERT INTO dbo.TempTable
VALUES 
('AB53EDH','2013/07/03 10:00', 54,23),
('AB53EDH','2013/07/03 10:01', 54,23),
('AB53EDH','2013/07/03 10:45', 54,23),
('AB53EDH','2013/07/03 10:46', 54,NULL),
('AB53EDH','2013/07/03 10:47', 54,NULL),
('AB53EDH','2013/07/03 11:05', 54,NULL),
('AB53EDH','2013/07/03 11:06', 54,102),
('AB53EDH','2013/07/03 11:07', 54,102),
('AB53EDH','2013/07/03 12:32', 54,102),
('AB53EDH','2013/07/03 12:33', 72,102),
('AB53EDH','2013/07/03 12:34', 72,102),
('AB53EDH','2013/07/03 13:00', 54,102),
('AB53EDH','2013/07/03 13:01', 54,102),
('AB53EDH','2013/07/03 13:02', 54,102),
('AB53EDH','2013/07/03 13:03', 54,102),
('AB53EDH','2013/07/03 13:04', 54,23),
('AB53EDH','2013/07/03 13:05', 54,23),
('AB53EDH','2013/07/03 13:06', 54,23),
('AB53EDH','2013/07/03 13:07', 54,NULL),
('AB53EDH','2013/07/03 13:08', 54,NULL),
('AB53EDH','2013/07/03 13:09', 54,NULL),
('AB53EDH','2013/07/03 13:10', 54,NULL),
('AB53EDH','2013/07/03 13:11', NULL,NULL)

INSERT INTO dbo.TempTable
SELECT Registration, DATEADD(M, -1, Date), DriverID, TrailerID
FROM dbo.TempTable
WHERE Date > '2013/07/01'

INSERT INTO dbo.TempTable
SELECT Registration, DATEADD(M, 1, Date), DriverID, TrailerID
FROM dbo.TempTable
WHERE Date > '2013/07/01'

Answer 1

此查询使用 CTE 来:

创建按注册分组的有序记录集合

对于每条记录，捕获上一条记录的数据

比较当前和以前的数据以确定当前记录是否
是司机/拖车分配的新实例

仅获取新记录

对于每条新记录，获取新司机/拖车前的最后日期
分配发生

链接到 SQL Fiddle

代码如下:

;WITH c AS (
-- Group records by Registration, assign row numbers in order of date
SELECT
  ROW_NUMBER() OVER (
    PARTITION BY Registration 
    ORDER BY Registration, [Date]) 
  AS Rn,
  Registration,
  [Date],
  DriverID,
  TrailerID
FROM 
  TempTable
)
,c2 AS (
-- Self join to table to get Driver and Trailer from previous record
SELECT 
  t1.Rn,
  t1.Registration,
  t1.[Date],
  t1.DriverID,
  t1.TrailerID,
  t2.DriverID AS PrevDriverID,
  t2.TrailerID AS PrevTrailerID
FROM 
  c t1
LEFT OUTER JOIN 
  c t2
ON 
  t1.Registration = t2.Registration
AND 
  t2.Rn = t1.Rn - 1 
)
,c3 AS (
-- Use INTERSECT to determine if this record is new in sequence
SELECT
  Rn,
  Registration,
  [Date],
  DriverID,
  TrailerID,
  CASE WHEN NOT EXISTS (
            SELECT DriverID, TrailerID 
            INTERSECT 
            SELECT PrevDriverID, PrevTrailerID) 
       THEN 1
       ELSE 0
  END AS IsNew
FROM c2 
) 
-- For all new records in sequence, 
-- get the last date logged before a new record appeared
SELECT 
  Registration,
  [Date] AS StartDate,
  COALESCE (
    (
       SELECT TOP 1 [Date]
       FROM c3 
       WHERE Registration = t.Registration
       AND Rn < (
         SELECT TOP 1 Rn
         FROM c3 
         WHERE Registration = t.Registration 
         AND Rn > t.Rn 
         AND IsNew = 1 
         ORDER BY Rn )
       ORDER BY Rn DESC 
    )
    , [Date]) AS EndDate,
  DriverID,
  TrailerID
FROM 
  c3 t
WHERE
  IsNew = 1 
ORDER BY 
  Registration,
  StartDate