SQL如何将具有日期范围的行转换为每个日期的多行

Question

如果我有一张像这样的桌子

begin date      end date        data
 2013-01-01     2013-01-04       7
 2013-01-05     2013-01-06       9

这样退货怎么办...

    date         data
 2013-01-01       7
 2013-01-02       7
 2013-01-03       7
 2013-01-04       7
 2013-01-05       9
 2013-01-06       9

我想做的一件事是有另一个只有所有日期的表，然后使用

date>=begin date

和

date<=end date

将只有日期的表连接到上表，但这似乎有点笨拙，必须保持额外的表格只有重复的日期。

在某些情况下，我没有数据范围，只有

as of

日期，这基本上看起来像我的第一个示例，但没有

end date

。

end date

由下一行的“截至”日期暗示（即结束日期应为下一行的

as of

-1）。我对此有一个“解决方案”，它使用 row_number() 函数来获取下一个值，但我怀疑这种方法（我这样做的方式有一堆嵌套的自连接）会导致查询时间很长。

Answer 1

使用一些示例数据...

create table data (begindate datetime, enddate datetime, data int);
insert data select 
 '20130101', '20130104', 7 union all select
 '20130105', '20130106', 9;

查询：（注意：如果您已经有一个数字/理货表 - 使用它）

select dateadd(d,v.number,d.begindate) adate, data
  from data d
  join master..spt_values v on v.type='P'
       and v.number between 0 and datediff(d, begindate, enddate)
order by adate;

结果：

|                       COLUMN_0 | DATA |
-----------------------------------------
| January, 01 2013 00:00:00+0000 |    7 |
| January, 02 2013 00:00:00+0000 |    7 |
| January, 03 2013 00:00:00+0000 |    7 |
| January, 04 2013 00:00:00+0000 |    7 |
| January, 05 2013 00:00:00+0000 |    9 |
| January, 06 2013 00:00:00+0000 |    9 |

---

或者，您可以动态生成一个数字表 (0-99) 或根据需要生成任意数量的数字

;WITH Numbers(number) AS (
  select top(100) row_number() over (order by (select 0))-1
  from sys.columns a
  cross join sys.columns b
  cross join sys.columns c
  cross join sys.columns d
  )
select dateadd(d,v.number,d.begindate) adate, data
  from data d
  join Numbers v on v.number between 0 and datediff(d, begindate, enddate)
order by adate;

SQL 小提琴演示

Answer 2

您可以使用递归 CTE 获取两个日期之间的所有日期。另一个 CTE 是获取 ROW_NUMBER 来帮助您处理那些缺少的 EndDates。

DECLARE @startDate DATE
DECLARE @endDate DATE

SELECT @startDate = MIN(begindate) FROM Table1
SELECT @endDate = MAX(enddate) FROM Table1

;WITH CTE_Dates AS 
(
    SELECT @startDate AS DT
    UNION ALL
    SELECT DATEADD(DD, 1, DT)
    FROM CTE_Dates
    WHERE DATEADD(DD, 1, DT) <= @endDate
)
,CTE_Data AS 
(
    SELECT *, ROW_NUMBER() OVER (ORDER BY BeginDate) AS RN FROM Table1

)
SELECT DT, t1.data FROM CTE_Dates d
LEFT JOIN CTE_Data t1 on d.DT 
BETWEEN t1.[BeginDate] AND COALESCE(t1.EndDate, 
        (SELECT DATEADD(DD,-1,t2.BeginDate) FROM CTE_Data t2 WHERE t1.RN + 1 = t2.RN))

SQLFiddle 演示

Answer 3

DECLARE @tblDateRange TABLE (
    Id INT,
    FromDateTime DATETIME,
    ToDateTime DATETIME
)
INSERT INTO @tblDateRange (Id, FromDateTime, ToDateTime)
VALUES
(1, '2023-01-01 10:00:00.000', '2023-01-01 10:00:00.000'),      --starts and ends in same
(2, '2023-02-02 00:00:00.000', '2023-02-04 23:59:59.000'),      --starts and ends in standered
(3, '2023-03-05 10:00:00.000', '2023-03-06 23:59:59.000'),      --starts in middle of another date
(4, '2023-04-07 00:00:00.000', '2023-04-08 21:00:00.000'),      --ends in middle of another date
(5, '2023-05-09 11:00:00.000', '2023-05-11 11:00:00.000'),      --starts and ends in middle of another date
(6, '2023-06-01 10:00:00.000', '2023-06-01 22:00:00.000');      --starts and ends in middle of same date


WITH DateRanges(Id, FromDateTime, ToDateTime, LevelNo, [Date], DateWiseStartDateTime, DateWiseEndDateTime)
AS
(
    SELECT 
        p.*,
        1,
        CAST(p.FromDateTime AS DATE),
        p.FromDateTime,
        IIF(DATEADD(SECOND, -1, DATEADD(DAY, DATEDIFF(DAY, 0, p.FromDateTime) + 1, 0)) < p.ToDateTime, DATEADD(SECOND, -1, DATEADD(DAY, DATEDIFF(DAY, 0, p.FromDateTime) + 1, 0)),  p.ToDateTime)   
    FROM @tblDateRange p
    UNION ALL
    SELECT 
        c.*,
        p.LevelNo + 1,
        CAST(DATEADD(DAY, DATEDIFF(DAY, 0, DATEADD(DAY, 1, p.DateWiseStartDateTime)), 0) AS DATE),
        DATEADD(DAY, DATEDIFF(DAY, 0, DATEADD(DAY, 1, p.DateWiseStartDateTime)), 0),
        IIF(c.ToDateTime < DATEADD(DAY, 1, p.DateWiseEndDateTime), c.ToDateTime, DATEADD(DAY, 1, p.DateWiseEndDateTime))
    FROM @tblDateRange c
    JOIN DateRanges p ON c.Id = p.Id
    WHERE DATEADD(DAY, DATEDIFF(DAY, 0, DATEADD(DAY, 1, p.DateWiseStartDateTime)), 0) < c.ToDateTime    --date wise start datetime < range to datetime
)
SELECT *
FROM DateRanges
ORDER BY Id, LevelNo
OPTION (MAXRECURSION 30000) --max 32767, no limit 0