SQL

Question

我有以下 table，除了其他属性外还包含：

ID - 唯一标识符
第 1 列
第 2 列
第 3 列
CreatedDate - 创建记录的时间（基于 ETL）
UpdatedDate - 直到记录有效

由于正在跟踪 3 列之外的其他属性以获取历史值，因此可能会出现这样的情况：对于同一 ID，所有三列的多行具有相同的值，但时间戳不同在 [创建日期] / [更新日期]。因此，数据可能如下所示：

ID	Column1	Column2	Column3	CreatedDate	UpdatedDate
1122	T1	In Progress	NULL	02/02/2022 18:39:38	29/03/2022 14:25:24
1122	T1	In Progress	NULL	05/01/2022 10:45:50	02/02/2022 18:39:38
1122	T1	In Progress	NULL	03/01/2022 12:11:47	05/01/2022 10:45:50
1122	T1	In Progress	Yes	13/12/2021 21:43:44	03/01/2022 12:11:47
1122	T1	In Progress	NULL	17/02/2021 14:12:15	13/12/2021 21:43:44
1122	T1	In Progress	NULL	22/12/2020 14:38:32	17/02/2021 14:12:15
1122	T1	In Progress	NULL	17/12/2020 18:38:38	22/12/2020 14:38:32
1122	T3	Ready	NULL	30/03/2020 14:35:18	17/12/2020 18:38:38
1122	NULL	Ready	NULL	04/09/2019 18:33:24	30/03/2020 14:35:18
1122	T2	Ready	NULL	07/01/2019 11:07:39	04/09/2019 18:33:24
1122	T2	Ready	NULL	17/09/2018 14:31:17	07/01/2019 11:07:39
1122	T0	Ready	NULL	28/08/2018 14:31:39	17/09/2018 14:31:17
1122	T0	Ready	NULL	13/02/2018 14:48:44	28/08/2018 14:31:39

我想以正确的顺序保留所有 3 列的唯一值，因此理想的输出应该如下所示：

ID	Column1	Column2	Column3	CreatedDate	UpdatedDate
1122	T1	In Progress	NULL	03/01/2022 12:11:47	29/03/2022 14:25:24
1122	T1	In Progress	Yes	13/12/2021 21:43:44	03/01/2022 12:11:47
1122	T1	In Progress	NULL	17/12/2020 18:38:38	13/12/2021 21:43:44
1122	T3	Ready	NULL	30/03/2020 14:35:18	17/12/2020 18:38:38
1122	NULL	Ready	NULL	04/09/2019 18:33:24	30/03/2020 14:35:18
1122	T2	Ready	NULL	17/09/2018 14:31:17	04/09/2019 18:33:24
1122	T0	Ready	NULL	13/02/2018 14:48:44	17/09/2018 14:31:17

如果只有一列，下面的代码工作正常，但它不适用于多列，因为它 returns 所有唯一行。

select ID, Column1, Column2, Column3,  min(createddate), max(updateddate)
from (select t.*,
             sum(case when prev_updatedate >= createddate then 0 else 1 end) over (partition by ID order by createddate) as grp
      from (select h.*,
                   max(updateddate) over (partition by ID order by createddate rows between unbounded preceding and 1 preceding) as prev_updatedate
            from #history h
           ) h
     ) h
group by ID, Column1, Column2, Column3, grp;

请问有什么解决办法吗？

Answer 1

你可以尝试使用ROW_NUMBER window函数来弥补你的逻辑差距然后你可能会得到gaps-and-islands

的分组

SELECT ID,Column1,Column2,Column3, min(createddate) CreatedDate, max(updateddate) UpdatedDate
FROM ( 
  select *,
      ROW_NUMBER() over (partition by ID order by createddate) - 
      ROW_NUMBER() over (partition by ID,Column1,Column2,Column3 order by createddate) grp
  from history
) t1
GROUP BY grp,ID,Column1,Column2,Column3
ORDER BY CreatedDate DESC

sqlfiddle

SQL - 更多属性的间隙和孤岛问题

SQL - gap and island issue for more attributes

sql-server

gaps-and-islands