Sql 将“从”&“到”日期列展开到该范围内每天1行

以以下示例数据为例：

WITH SampleData AS (
    SELECT '8000213' AS EmployeeID, '2014-08-25 00:00:00.000' AS StartDate, '2014-08-31 00:00:00.000' AS EndDate, 28.5 AS HPW
    UNION ALL
    SELECT '8000213' AS EmployeeID, '2014-10-01 00:00:00.000' AS StartDate, NULL AS EndDate, 33 AS HPW
    UNION ALL
    SELECT '0003289' AS EmployeeID, '2014-04-25 00:00:00.0000' AS StartDate, '2014-04-30 00:00:00.000' AS EndDate, 36 AS HPW
    UNION ALL
    SELECT '0003289' AS EmployeeID, '2014-05-01 00:00:00.000' AS StartDate, NULL AS EndDate, 20 AS HPW
)
SELECT * FROM SampleData

如果没有结束日期，假设当前日期，我们如何按如下方式扩展此数据：

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我怀疑这里需要某种递归/CTE/理货表，但我不能完全理解它

制作日期生成器有很多不同的方法；整篇文章都在讨论哪一个是最快的，但为了简单起见，我将对找到的那个进行调整。我建议您阅读一下这个主题，并在数据库中持久化一个真实的日期表，以便用于类似这样的查询，而不是为执行的每个查询动态生成一个

第一步：创建一个日期表

第二步：将表中的每个日期与员工关联注意：我还对其进行筛选，以便在SampleData中仅显示大于最小开始日期的日期

第三步：将日期/不同的员工加入到您的数据中，以检索自给定日期起生效的HPW

SQL:

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或者，您可以简单地继续CTE：

--Replace the enddate with "Getdate()" if you require expansion until "today/current"
Declare @DefaultEnddate Datetime = '2014-10-15 00:00:00.000'

;WITH SampleData AS (
SELECT '8000213' AS EmployeeID, '2014-08-25 00:00:00.000' AS StartDate, '2014-08-31 00:00:00.000' AS EndDate, 28.5 AS HPW
UNION ALL
SELECT '8000213' AS EmployeeID, '2014-10-01 00:00:00.000' AS StartDate, NULL AS EndDate, 33 AS HPW
UNION ALL
SELECT '0003289' AS EmployeeID, '2014-04-25 00:00:00.000' AS StartDate, '2014-04-30 00:00:00.000' AS EndDate, 36 AS HPW
UNION ALL
SELECT '0003289' AS EmployeeID, '2014-05-01 00:00:00.000' AS StartDate, NULL AS EndDate, 20 AS HPW
)
, Base as ( SELECT EmployeeID, StartDate = Convert(datetime, StartDate) , EndDate = Convert(datetime,isnull(EndDate,@DefaultEnddate)), HPW FROM SampleData)
, Expanded as (Select EmployeeID, StartDate as [Date], HPW , EndDate from Base
                union all
                Select EmployeeID, [Date] = [Date] + 1, HPW , EndDate from Expanded where [Date] < EndDate
        )
select EmployeeID,[Date], HPW
from Expanded 
Order by EmployeeID, [Date]
OPTION (MAXRECURSION 1000)

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创建生成器并与表联接。

--Replace the enddate with "Getdate()" if you require expansion until "today/current"
Declare @DefaultEnddate Datetime = '2014-10-15 00:00:00.000'

;WITH SampleData AS (
SELECT '8000213' AS EmployeeID, '2014-08-25 00:00:00.000' AS StartDate, '2014-08-31 00:00:00.000' AS EndDate, 28.5 AS HPW
UNION ALL
SELECT '8000213' AS EmployeeID, '2014-10-01 00:00:00.000' AS StartDate, NULL AS EndDate, 33 AS HPW
UNION ALL
SELECT '0003289' AS EmployeeID, '2014-04-25 00:00:00.000' AS StartDate, '2014-04-30 00:00:00.000' AS EndDate, 36 AS HPW
UNION ALL
SELECT '0003289' AS EmployeeID, '2014-05-01 00:00:00.000' AS StartDate, NULL AS EndDate, 20 AS HPW
)
, Base as ( SELECT EmployeeID, StartDate = Convert(datetime, StartDate) , EndDate = Convert(datetime,isnull(EndDate,@DefaultEnddate)), HPW FROM SampleData)
, Expanded as (Select EmployeeID, StartDate as [Date], HPW , EndDate from Base
                union all
                Select EmployeeID, [Date] = [Date] + 1, HPW , EndDate from Expanded where [Date] < EndDate
        )
select EmployeeID,[Date], HPW
from Expanded 
Order by EmployeeID, [Date]
OPTION (MAXRECURSION 1000)