Question

用户指定可用时，这些指定时间可以重叠。我正在努力获得他们可用的总时间。 SQL小提琴示例：

--Available--
ID  userID  availStart          availEnd
1   456     '2012-11-19 16:00'  '2012-11-19 17:00'
2   456     '2012-11-19 16:00'  '2012-11-19 16:50'
3   456     '2012-11-19 18:00'  '2012-11-19 18:30'
4   456     '2012-11-19 17:30'  '2012-11-19 18:10'
5   456     '2012-11-19 16:00'  '2012-11-19 17:10'
6   456     '2012-11-19 16:00'  '2012-11-19 16:50'

输出应为130分钟：

1: 60
2: 0 as falls inside 1
3: 30
4: 30 as the last 10 mins is covered by 3
5: 10 as first 60 mins is covered by 1
6: 0 as falls inside 1

我可以获得总重叠分钟数，但这超过了可用分钟数的总和：

SQL Fiddle

我是如何实现这一目标的？

编辑11月21日：感谢所有人的解决方案 - 在某种程度上，我很高兴看到这不是一个'简单'的查询。

编辑11月23日11月：这都是出色的工作。在内部，我们认为最好确保用户不能输入重叠时间（例如强制他们修改现有条目）！

Answer 1

Gordon Linoff有CTE based answer

我在所有工作算法上都做了一些performance analysis 空白值意味着花了太长时间。这是在单个Core i7 X920 @ 2GHz芯片上测试的，由几个SSD支持。创建的唯一索引是UserID上的集群，AvailStart。如果您认为可以改善任何表现，请告诉我。

这个CTE版本比线性更差，SQL Server无法以有效的方式进行RN = RN + 1加入。我使用下面的混合方法对此进行了纠正，我将第一个CTE保存并索引到表变量中。这仍然是基于光标的方法的IO的十倍。

With OrderedRanges as (
  Select
    Row_Number() Over (Partition By UserID Order By AvailStart) AS RN,
    AvailStart,
    AvailEnd
  From
    dbo.Available
  Where
    UserID = 456
),
AccumulateMinutes (RN, Accum, CurStart, CurEnd) as (
  Select
    RN, 0, AvailStart, AvailEnd
  From
    OrderedRanges
  Where 
    RN = 1
  Union All
  Select
    o.RN, 
    a.Accum + Case When o.AvailStart <= a.CurEnd Then
        0
      Else 
        DateDiff(Minute, a.CurStart, a.CurEnd)
      End,
    Case When o.AvailStart <= a.CurEnd Then 
        a.CurStart
      Else
        o.AvailStart
      End,
    Case When o.AvailStart <= a.CurEnd Then
        Case When a.CurEnd > o.AvailEnd Then a.CurEnd Else o.AvailEnd End
      Else
        o.AvailEnd
      End
  From
    AccumulateMinutes a
        Inner Join 
    OrderedRanges o On 
        a.RN = o.RN - 1
)

Select Max(Accum + datediff(Minute, CurStart, CurEnd)) From AccumulateMinutes

http://sqlfiddle.com/#!6/ac021/2

在做了一些性能分析之后，这里是一个混合的CTE /表变量版本，除了基于游标的方法之外，它的性能要好于其他任何东西

Create Function dbo.AvailMinutesHybrid(@UserID int) Returns Int As
Begin

Declare @UserRanges Table (
  RN int not null primary key, 
  AvailStart datetime, 
  AvailEnd datetime
)
Declare @Ret int = Null

;With OrderedRanges as (
  Select
    Row_Number() Over (Partition By UserID Order By AvailStart) AS RN,
    AvailStart,
    AvailEnd
  From
    dbo.Available
  Where
    UserID = @UserID
)
Insert Into @UserRanges Select * From OrderedRanges


;With AccumulateMinutes (RN,Accum, CurStart, CurEnd) as (
  Select
    RN, 0, AvailStart, AvailEnd
  From
    @UserRanges
  Where 
    RN = 1
  Union All
  Select
    o.RN, 
    a.Accum + Case When o.AvailStart <= a.CurEnd Then
        0
      Else 
        DateDiff(Minute, a.CurStart, a.CurEnd)
      End,
    Case When o.AvailStart <= a.CurEnd Then 
        a.CurStart
      Else
        o.AvailStart
      End,
    Case When o.AvailStart <= a.CurEnd Then
        Case When a.CurEnd > o.AvailEnd Then a.CurEnd Else o.AvailEnd End
      Else
        o.AvailEnd
      End
  From
    AccumulateMinutes a
        Inner Join 
    @UserRanges o On 
        a.RN + 1 = o.RN
)

Select 
  @Ret = Max(Accum + datediff(Minute, CurStart, CurEnd)) 
From 
  AccumulateMinutes 
Option
  (MaxRecursion 0)

Return @Ret

End

http://sqlfiddle.com/#!6/bfd94

Answer 2

主要问题是你可以拥有重叠条目的链，所以你需要无限次地组合来删除所有重叠 - 这比SQL更适合于程序方法。但是如果你不想使用临时表，那么这是一个CTE方法 - 请记住，CTE只能递归给定次数，所以如果你有任何特别长的链，它就会失败。

WITH MergedAvailable
AS
(
  SELECT Available.UserID, Available.AvailStart, MAX(Available.AvailEnd) AS AvailEnd
    FROM Available
   WHERE (
           SELECT COUNT(*)
             FROM Available AS InnerAvailable
            WHERE InnerAvailable.AvailStart < Available.AvailStart
                  AND
                  InnerAvailable.AvailEnd >= Available.AvailStart
         ) = 0
   GROUP BY Available.UserID, Available.AvailStart
  UNION ALL
  SELECT MergedAvailable.UserID, MergedAvailable.AvailStart,
         LongestExtensionToAvailableInterval.NewIntervalEnd
    FROM MergedAvailable
   CROSS APPLY GetLongestExtensionToAvailableInterval(MergedAvailable.UserID,
               MergedAvailable.AvailStart,
               MergedAvailable.AvailEnd) AS LongestExtensionToAvailableInterval
   WHERE LongestExtensionToAvailableInterval.NewIntervalEnd IS NOT NULL
)

SELECT SUM(DATEDIFF(MINUTE,
                    FinalAvailable.AvailStart,
                    FinalAvailable.AvailEnd)) AS MinsAvailable
  FROM (
         SELECT MergedAvailable.UserID, MergedAvailable.AvailStart,
                MAX(MergedAvailable.AvailEnd) AS AvailEnd
           FROM MergedAvailable
          GROUP BY MergedAvailable.UserID, MergedAvailable.AvailStart
       ) AS FinalAvailable

此表功能是必需的：

CREATE FUNCTION GetLongestExtensionToAvailableInterval
(
  @UserID int,
  @CurrentIntervalStart datetime,
  @CurrentIntervalEnd datetime
)
RETURNS TABLE
AS
RETURN 
  SELECT MAX(Available.AvailEnd) AS NewIntervalEnd
    FROM Available
   WHERE Available.UserID = @UserID
         AND
         Available.AvailStart > @CurrentIntervalStart
         AND
         Available.AvailStart <= @CurrentIntervalEnd
         AND
         Available.AvailEnd > @CurrentIntervalEnd

一般的想法是，它从范围的起点不重叠的所有范围开始，然后在每次递归时，它将当前范围扩展到当前重叠范围的最远范围。需要表函数来确定最远的范围，因为CTE的递归部分不允许包含普通聚合。

根据您提供的数据，起始行为：

456 2012-11-19 16:00 2012-11-19 17:10
456 2012-11-19 17:30 2012-11-19 18:10

最后通过递归添加的唯一行是：

456 2012-11-19 17:30 2012-11-19 18:30

为了这个例子，假设你有一行ID为7，从18:20到19:20。然后会有第二次递归带回行：

456 2012-11-19 17:30 2012-11-19 19:20

因此，当查询将到达每个重叠范围的开始和结束时，它也将带回所有中间阶段。这就是为什么我们需要在CTE之后的每个开始日期采用聚合最大结束日期来删除它们。

Answer 3

这是使用游标执行此操作的另一种方法。我觉得这个技术应该适应CTE，但我无法弄清楚如何做到这一点

方法是按开始时间排列每个范围然后我们建立一个范围，按顺序合并范围，直到找到与我们的合并范围不重叠的范围。然后我们计算合并范围内的分钟数，并记住这一点我们继续使用下一个范围，再次合并任何重叠范围。每当我们得到一个非重叠的起点时，我们会累积分钟最后，我们将累积的分钟数添加到最后一个范围的长度

很容易看出，由于顺序，一旦范围不同之前没有进一步的范围可能与之前的情况重叠，就像他们的情况一样开始日期都更长。

Declare
  @UserID int = 456,
  @CurStart datetime, -- our current coalesced range start
  @CurEnd datetime, -- our current coalsced range end
  @AvailStart datetime, -- start or range for our next row of data
  @AvailEnd datetime, -- end of range for our next row of data
  @AccumMinutes int = 0 -- how many minutes so far accumulated by distinct ranges

Declare MinCursor Cursor Fast_Forward For
Select
  AvailStart, AvailEnd
From
  dbo.Available
Where
  UserID = @UserID
Order By
  AvailStart

Open MinCursor

Fetch Next From MinCursor Into @AvailStart, @AvailEnd
Set @CurStart = @AvailStart
Set @CurEnd = @AvailEnd

While @@Fetch_Status = 0
Begin
  If @AvailStart <= @CurEnd -- Ranges Overlap, so coalesce and continue
    Begin
    If @AvailEnd > @CurEnd 
      Set @CurEnd = @AvailEnd
    End
  Else -- Distinct range, coalesce minutes from previous range
  Begin
    Set @AccumMinutes = @AccumMinutes + DateDiff(Minute, @CurStart, @CurEnd)
    Set @CurStart = @AvailStart -- Start coalescing a new range
    Set @CurEnd = @AvailEnd
  End
  Fetch Next From MinCursor Into @AvailStart, @AvailEnd
End

Select @AccumMinutes + DateDiff(Minute, @CurStart, @CurEnd) As TotalMinutes

Close MinCursor
Deallocate MinCursor;

http://sqlfiddle.com/#!6/3483c/15

Answer 4

条件 t1.availStart＆gt; t2.availEnd OR t1.availEnd＆lt; t2.availStart 检查永远不会越过的期间。如果超过则最小availStart或最大availEnd esle availStart或availEnd。

Probably more than one crossing period.
In your case it 
16:00:00 - 17:10:00 includes the ranges:16:00:00 - 16:50:00,
                                        16:00:00 - 16:50:00,
                                        16:00:00 - 17:00:00,
                                        16:00:00 - 17:10:00
17:30:00 - 18:30:00 includes the ranges:17:30:00 - 18:10:00,
                                        18:00:00 - 18:30:00

更新21.11.2012; 2012年11月30日; 2013年4月1日

CREATE FUNCTION dbo.Overlap
 (
  @availStart datetime,
  @availEnd datetime,
  @availStart2 datetime,
  @availEnd2 datetime
  )
RETURNS TABLE
RETURN
  SELECT CASE WHEN @availStart >= @availEnd2 OR @availEnd <= @availStart2
              THEN @availStart ELSE
                               CASE WHEN @availStart > @availStart2 THEN @availStart2 ELSE @availStart END
                               END AS availStart,
         CASE WHEN @availStart >= @availEnd2 OR @availEnd <= @availStart2
              THEN @availEnd ELSE
                             CASE WHEN @availEnd > @availEnd2 THEN @availEnd ELSE @availEnd2 END
                             END AS availEnd

;WITH cte AS
 (
  SELECT userID, availStart, availEnd, ROW_NUMBER() OVER (PARTITION BY UserID ORDER BY AvailStart) AS Id
  FROM dbo.test53
  ), cte2 AS
 (
  SELECT Id, availStart, availEnd
  FROM cte
  WHERE Id = 1
  UNION ALL
  SELECT c.Id, o.availStart, o.availEnd
  FROM cte c JOIN cte2 ct ON c.Id = ct.Id + 1
             CROSS APPLY dbo.Overlap(c.availStart, c.availEnd, ct.availStart, ct.availEnd) AS o
  )
  SELECT TOP 1 SUM(DATEDIFF(minute, availStart, MAX(availEnd))) OVER()
  FROM cte2
  GROUP BY availStart

SQLFiddle上的演示

Answer 5

Create Table #Available (
  ID int not null primary key,
  UserID int not null,
  AvailStart datetime not null,
  AvailEnd datetime not null
)


Insert Into #Available (ID,UserID, AvailStart, AvailEnd) Values
  (1,456, '2012-11-19 16:00', '2012-11-19 17:00'),
  (2,456, '2012-11-19 16:00', '2012-11-19 16:50'),
  (3,456, '2012-11-19 18:00', '2012-11-19 18:30'),
  (4,456, '2012-11-19 17:30', '2012-11-19 18:10'),
  (5,456, '2012-11-19 16:00', '2012-11-19 17:10'),
  (6,456, '2012-11-19 16:00', '2012-11-19 16:50'),
  (7,457, '2012-11-19 16:00', '2012-11-19 17:10'),
  (8,457, '2012-11-19 16:00', '2012-11-19 16:50');  
Select Distinct UserID 
into #users
from #Available


Create Table #mins(UserID int,atime datetime,aset tinyint )
Declare @start Datetime
Declare @end Datetime

Select @start=min(AvailStart),@end=max(AvailEnd) from #Available 
While @start<@end
    begin
     insert into #mins(UserID,atime) 
     Select UserID ,@Start from #users
     Select @start=DateAdd(mi,1,@start)
    end

update #mins set aset=1
from #Available
where atime>=AvailStart and atime<Availend and #mins.UserID = #Available.UserID


select UserID,SUM(aset) as [Minutes] 
from #mins
Group by UserID 
Drop table #Available
Drop table #mins
Drop table #users

多个日期范围之间的分钟总和

5 个答案: