Sql 需要删除重复数据吗

下面是我通过两个临时表之间的简单联接获得的表。现在预期的结果有点难以解释，我甚至不知道从哪里开始。因此，我将发布预期结果，并回答可能出现的任何问题

编辑：基本上需要两列中的每个日期只显示一次

+----+------------------+----------------+----------------------+-----------     ---------+-----------------------+---------------------+
| ID | Date from Source | Date to source | From Source Revision | To source Revision | From Source InstantID | To Source InstantID |
+----+------------------+----------------+----------------------+--------------------+-----------------------+---------------------+
| 45 | 2015-06-19       | 2015-07-06     | P0                   | P0                 |                     1 |                   3 |
| 45 | 2015-06-19       | 2015-07-09     | P0                   | P0                     |                     1 |                   5 |
| 45 | 2015-07-27       | 2015-07-06     | P0                   | P0                 |                     6 |                   3 |
| 45 | 2015-07-27       | 2015-07-09     | P0                   | P0                 |                     6 |                   5 |
| 45 | 2015-07-28       | 2015-07-06     | P0                   | P0                 |                     7 |                   3 |
| 45 | 2015-07-28       | 2015-07-09     | P0                   | P0                 |                     7 |                   5 |
| 45 | 2015-07-30       | 2015-07-06     | P0                   | P0                 |                     8 |                   3 |
| 45 | 2015-07-30       | 2015-07-09     | P0                   | P0                  |                     8 |                   5 |
+----+------------------+----------------+----------------------+--------------------+-----------------------+---------------------+

预期结果

+----+------------------+----------------+----------------------+--------------------+-----------------------+---------------------+
| ID | Date from Source | Date to source | From Source Revision | To source Revision | From Source InstantID | To Source InstantID |
+----+------------------+----------------+----------------------+--------------------+-----------------------+---------------------+
| 45 | 19-06-2015       | 06-07-2015     | P0                   | P0                 |                     1 |                   3 |
| 45 |                  | 09-07-2015     | P0                   | P0                 |                       |                   5 |
| 45 | 27-07-2015       |                | P0                   | P0                 |                     6 |                     |
| 45 | 28-07-2015       |                | P0                   | P0                 |                     7 |                     |
| 45 | 30-07-2015       |                | P0                   | P0                 |                     8 |                     |
+----+------------------+----------------+----------------------+--------------------+-----------------------+---------------------+

试试这个：

DELETE FROM myTable WHERE Id IN (
    SELECT Id FROM (SELECT Id
   ,ROW_NUMBER() OVER (PARTITION BY [Date from Source] ORDER BY [Date from Source]) AS [rn]             
        FROM myTable 
    ) a WHERE rn > 1 
)

---

您是否尝试使用Select Distinct语句？我可以看到源中日期的类型行，因为19Jun和27July完全相同，但即使如此，为什么19Jun有两行，而27July和其余都是单行？查看您的输出数据，似乎您需要使用游标来实现这一点。您实际上不需要选择除RN之外的所有其他数据，对吗？另外，

DELETE FROM CTE

会知道如何引用实际表格吗？

CTE

不只是一个结果集吗？如果

CTE

将有多个

连接

，那么

删除

将如何工作？嗨@RaduGheorghiu，如果我提到我的结果集中只需要两个日期列，这有什么关系吗？@crasster:-更新了！