[jira] Commented: (DERBY-4397) Allow ORDER BY in subqueries

["Dag H. Wanvik (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DERBY-4397?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12798382#action_12798382 ] 

Dag H. Wanvik commented on DERBY-4397:
--------------------------------------

Found that sort avoidance fails in a FromSubquery:
If this query avoids sorting due to an index on i:

   select i from t order by i

one would expect this to avoid it as well:

   select * from (select i from t order by i) t

but I see that sorting is performed in the latter case. It would be nice to make it work in the latter case as well..

> Allow ORDER BY in subqueries
> ----------------------------
>
>                 Key: DERBY-4397
>                 URL: https://issues.apache.org/jira/browse/DERBY-4397
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>            Reporter: Dag H. Wanvik
>            Assignee: Dag H. Wanvik
>         Attachments: derby-4397-1.diff, derby-4397-1.stat, derby-4397-2.diff, derby-4397-2.stat, derby-4397-all-subqueries.diff, derby-4397-all-subqueries.stat, derby-4397-insert-from-exists.diff, derby-4397-insert-from-exists.stat, orderBySpec.html, orderBySpec.html, orderBySpec.html, orderBySpec.html, orderBySpec.html
>
>
> SQL 2008 allows ORDER BY to be specified in subqueries. In conjunction with OFFSET/FETCH and/or ROW_NUMBER
> meaningful subqueries with row ordering may be formulated. Cf. MySQL's LIMIT may be used in subqueries as well.
> Note that OFFSET/FETCH is currently not allowed in subqueries, either.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.