如何将日期范围表转换为基于行的视图？

Question

我正面临艰难的处境。到目前为止我找不到解决方案。

我有一个根据日期范围提供信息的表格。我想按日期细分这些信息。所以我希望将范围转换为行结构。

额外的困难是日期范围内的“句点”数量是可变的。 “周期”是从日期范围和一个周期的天数中扣除的。

更具体地说，在表格的一行我有一个

• 身份证
• 范围的开始日期
• 范围的结束日期
• _in_the_period 天数
• numbers_periods
• 适用于该范围内每个时期的定价

这是初始表结构和预期结果：

CREATE TABLE Start(
 Key                VARCHAR(11) NOT NULL PRIMARY KEY
,Start_date         VARCHAR(27) NOT NULL
,End_Date           VARCHAR(27) NOT NULL
,Days_in_the_period INTEGER  NOT NULL
,Nbr_periods        INTEGER  NOT NULL
,Pricing            VARCHAR(6) NOT NULL
);
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2000-06-01 00:00:00.0000000','2001-12-01 00:00:00.0000000',30,19,'800,87');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2002-01-01 00:00:00.0000000','2005-12-01 00:00:00.0000000',30,48,'440,32');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2006-01-01 00:00:00.0000000','2007-02-01 00:00:00.0000000',30,14,'282,68');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2007-03-01 00:00:00.0000000','2008-03-01 00:00:00.0000000',30,13,'283,99');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2008-04-01 00:00:00.0000000','2009-01-01 00:00:00.0000000',60,5,'281,81');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2009-02-01 00:00:00.0000000','2009-03-01 00:00:00.0000000',30,2,'281,81');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2009-04-01 00:00:00.0000000','2019-07-01 00:00:00.0000000',30,124,'281,81');
INSERT INTO Start(Key,Start_date,End_Date,Days_in_the_period,Nbr_periods,Pricing) VALUES ('010-1280001','2019-08-01 00:00:00.0000000','2019-08-01 00:00:00.0000000',0,1,'372,96');

预期

  Key                  Date               Pricing   Days_in_the_period  

---

010-1280001 2000-06-01 00:00:00.0000000 800,87 30
010-1280001 2000-07-01 00:00:00.0000000 800,87 30
………………
010-1280001 2008-04-01 00:00:00.0000000 281,81 60
010-1280001 2008-06-01 00:00:00.0000000 281,81 60
………………
010-1280001 2019-08-01 00:00:00.0000000 372,96 0

关于信息，初始表包含大约 100k 条记录。 有人对我有一个绝妙的主意吗？

请回复任何澄清， 塔蒂诺。

Answer 1

您可以在递归 CTE 的帮助下做到这一点：

;WITH cte AS (
    SELECT  *
    FROM YourTable
    UNION ALL
    SELECT  c.[key],
            DATEADD(month,c.Days_in_the_period/30,c.[Start_Date]),
            c.End_Date,
            c.Days_in_the_period,
            c.Nbr_periods,
            c.Pricing
    FROM cte c
    INNER JOIN YourTable y
        ON y.[key] = c.[key] AND c.End_Date = y.End_Date
    WHERE y.End_Date >=DATEADD(month,c.Days_in_the_period/30,c.[Start_Date])
)


SELECT  [key],
        [Start_Date] as [Date],
        Pricing,
        Days_in_the_period
FROM cte
ORDER BY [key], [Start_Date]

另一种方法是使用日历表，并将其与您的表连接起来。