Oracle SQL组由单个字段组成,并计算分组的行数

Question

考虑一下这个表some_table:

+--------+----------+---------------------+-------+
| id     | other_id | date_value          | value |
+--------+----------+---------------------+-------+
| 1      | 1        | 2011-04-20 21:03:05 | 104   |
| 2      | 1        | 2011-04-20 21:03:04 | 229   |
| 3      | 3        | 2011-04-20 21:03:03 | 130   |
| 4      | 1        | 2011-04-20 21:02:09 | 97    |
| 5      | 2        | 2011-04-20 21:02:08 | 65    |
| 6      | 3        | 2011-04-20 21:02:07 | 101   |
| ...    | ...      | ...                 | ...   |
+--------+----------+---------------------+-------+

我想选择和分组other_id,以便我只获得独特other_id的.此查询有效(信用@MichaelPakhantsov):

select id, other_id, date_value, value from
 (
   SELECT id, other_id, date_value, value, 
   ROW_NUMBER() OVER (partition by other_id order BY Date_Value desc) r
   FROM some_table 
 )
 where r = 1

我如何获得相同的结果,但是每个都计算了分组的行数other_id.期望的结果如下:

+--------+----------+---------------------+-------+-------+
| id     | other_id | date_value          | value | count |
+--------+----------+---------------------+-------+-------+
| 1      | 1        | 2011-04-20 21:03:05 | 104   | 3     |
| 5      | 2        | 2011-04-20 21:02:08 | 65    | 2     |
| 3      | 3        | 2011-04-20 21:03:03 | 130   | 2     |
+--------+----------+---------------------+-------+-------+

我已尝试COUNT(other_id)在内部和外部选择中使用,但它会产生此错误:

ORA-00937:不是单组组功能

---

注意:类似于这个问题(示例表和从那里获得的答案),但该问题没有给出折叠行的计数.

Answer 1

添加一个

count(*) OVER (partition by other_id) cnt

到内部查询

select id, other_id, date_value, value, cnt from
 (
   SELECT id, other_id, date_value, value, 
   ROW_NUMBER() OVER (partition by other_id order BY Date_Value desc) r,
   count(*) OVER (partition by other_id) cnt
   FROM some_table 
 )
 where r = 1