SQL 如何根据数据列将具有日期范围的行转换为具有带间隙的日期范围的多行

SQL how to convert row with date range to many rows with date range with gaps based on a data column

我想根据列将数据行转换为 sql 中的日期范围。 以下是示例数据:

Current Data

FROMDATE    TODATE      Data
1/01/2010   31/10/2010  100
1/01/2011   31/12/2011  50
1/01/2012   31/12/2012  50
1/01/2013   31/12/2013  50
1/01/2014   31/12/2014  50
1/01/2015   12/10/2015  50
13/10/2015  31/12/2015  50
1/01/2016   21/02/2016  50
22/02/2016  31/12/2016  67
1/01/2017   2/10/2017   67
3/10/2017   31/12/2017  75
1/01/2018   31/03/2018  75
1/04/2018   30/06/2018  75
1/07/2018   31/10/2018  40
1/11/2018   31/12/2018  75
1/01/2019   31/03/2019  75
1/04/2019   31/12/2019  75
1/01/2020   1/03/2020   75

要求的结果是:

FROMDATE    TODATE      Data
1/01/2010   31/10/2010  100
1/01/2011   21/02/2016  50
22/02/2016  2/10/2017   67
3/10/2017   30/06/2018  75
1/07/2018   31/10/2018  40
1/11/2018   1/03/2020   75

Required List

我想感谢@Gordon Linoff,他 answer 中的一位帮助我解决了 Gaps 和 islands 问题,我只是与您分享这些问题。

我之所以将此作为答案发布是因为标题可以在此类问题的搜索结果中找到

我已经使用 Oracle 数据库完成了它,它应该适用于所有标准 sql 数据库。 dbfiddle供参考

SELECT t.key_id
      ,MIN(fromdate)
      ,MAX(todate)
FROM   (SELECT t.*
              ,row_number() over(ORDER BY fromdate) AS startseq
              ,row_number() over(PARTITION BY t.key_id ORDER BY fromdate) AS endseq
        FROM   some_table t) t
GROUP  BY t.key_id
         ,(startseq - endseq);