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Asked: 2026-06-17T12:15:13+00:00

In a nutshell I’m trying to group by a column but only if that

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In a nutshell I’m trying to group by a column but only if that column is not null or 0 in which case I still want to get those rows, but just not grouped. I have this table some_table:

+--------+----------+---------------------+-------+
| id     | other_id | date_value          | value |
+--------+----------+---------------------+-------+
| 1      | abc      | 2011-04-20 21:03:05 | 104   |
| 2      | abc      | 2011-04-20 21:03:04 | 229   |
| 3      | xyz      | 2011-04-20 21:03:03 | 130   |
| 4      | abc      | 2011-04-20 21:02:09 | 97    |
| 5      | 0        | 2011-04-20 21:02:08 | 65    |
| 6      | xyz      | 2011-04-20 21:02:07 | 101   |
| 7      |          | 2011-04-20 21:02:07 | 200   |
| 8      | 0        | 2011-04-20 21:02:07 | 201   |
| 9      |          | 2011-04-20 21:02:07 | 202   |
+--------+----------+---------------------+-------+

I wanted to select the rows and group by other_id, and also include a count of the grouped rows. This query works:

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

The result is:

+--------+----------+---------------------+-------+-------+
| id     | other_id | date_value          | value | count |
+--------+----------+---------------------+-------+-------+
| 1      | abc      | 2011-04-20 21:03:05 | 104   | 3     |
| 3      | xyz      | 2011-04-20 21:03:03 | 130   | 2     |
| 5      | 0        | 2011-04-20 21:02:08 | 65    | 2     |
| 7      |          | 2011-04-20 21:02:07 | 200   | 2     |
+--------+----------+---------------------+-------+-------+

The problem is, I don’t want to group the rows that have other_id of null or 0. So the desired result is this:

+--------+----------+---------------------+-------+-------+
| id     | other_id | date_value          | value | count |
+--------+----------+---------------------+-------+-------+
| 1      | abc      | 2011-04-20 21:03:05 | 104   | 3     |
| 3      | xyz      | 2011-04-20 21:03:03 | 130   | 2     |
| 5      | 0        | 2011-04-20 21:02:08 | 65    | 1     |
| 7      |          | 2011-04-20 21:02:07 | 200   | 1     |
| 8      | 0        | 2011-04-20 21:02:07 | 201   | 1     |
| 9      |          | 2011-04-20 21:02:07 | 202   | 1     |
+--------+----------+---------------------+-------+-------+

As you can see, everything is grouped except when other_id is null or 0 in which case they are still selected, but not grouped. I am also trying to order by the date_value.

I have tried adding a WHERE clause in the OVER clause:

OVER (partition by other_id WHERE other_id IS NOT NULL AND other_id IS NOT '0' order BY Date_Value desc)
-- this produces an error: ORA-00907: missing right parenthesis

I have thought about doing a second select query and trying to stack the first results on top of the second, but I don’t think that would work because of the ordering.

Is there any way of grouping like this with a condition?

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1 Answer

  1. Editorial Team

    this will do it:

    SQL> select id, other_id, date_value, value, cnt from
  2   (
  3     SELECT id, other_id, date_value, value,
  4     case
  5       when other_id is null or other_id = '0' then 1
  6       else ROW_NUMBER() OVER (partition by other_id order BY Date_Value desc)
  7     end r,
  8     case
  9       when other_id is null or other_id = '0' then 1
 10       else count(*) OVER (partition by other_id)
 11     end cnt
 12     FROM some_table
 13   )
 14  where r = 1
 15  order by id;

        ID OTH DATE_VALUE               VALUE        CNT
---------- --- ------------------- ---------- ----------
         1 abc 2011-04-20 21:03:05        104          3
         3 xyz 2011-04-20 21:03:03        130          2
         5 0   2011-04-20 21:02:08         65          1
         7     2011-04-20 21:02:07        200          1
         8 0   2011-04-20 21:02:07        201          1
         9     2011-04-20 21:02:07        202          1

6 rows selected.

SQL>
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