[
https://issues.apache.org/jira/browse/DERBY-4371?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12900327#action_12900327
]
Knut Anders Hatlen commented on DERBY-4371:
-------------------------------------------
> Should we allow following type of queries:
> "select distinct i from t order by i/j;"
No, this query should not be allowed. Consider the table
i | j | i/j
---------------
100 | 10 | 10
100 | 100 | 1
200 | 40 | 5
3 | 1 | 3
Here, the ORDER BY clause is ambiguous, because it's not clear whether
100 should be the first value or the last value in the result.
> Non-selected columns for SELECT DISTINCT allowed in ORDER BY clause if
> ordered by expression
> --------------------------------------------------------------------------------------------
>
> Key: DERBY-4371
> URL: https://issues.apache.org/jira/browse/DERBY-4371
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.5.1.1
> Reporter: Bernt M. Johnsen
> Assignee: C.S. Nirmal J. Fernando
> Priority: Critical
> Attachments: DERBY-4371-2.diff, DERBY-4371-3.diff, DERBY-4371-4.diff,
> derby-4371-5.diff, DERBY-4371.diff
>
>
> How to repeat:
> ij> create table t (i integer, j integer);;
> 0 rows inserted/updated/deleted
> ij> insert into t values (1,2),(1,3);
> 2 rows inserted/updated/deleted
> ij> select distinct i from t order by j;
> ERROR 42879: The ORDER BY clause may not contain column 'J', since the query
> specifies DISTINCT and that column does not appear in the query result.
> ij> select distinct i from t order by j*2;
> I
> -----------
> 1
> 1
> 2 rows selected
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
