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https://issues.apache.org/jira/browse/DERBY-2998?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12572498#action_12572498
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Thomas Nielsen commented on DERBY-2998:
---------------------------------------
The resultset number problem is a little strange. The following query runs fine:
select * from (select row_number() over (), t.a from t) as tr;
but flip the column order, and it fails:
select * from (select t.a, row_number() over () from t) as tr;
With both queries we run fine until we eventually end up in
ResultColumnList.generateCore() in a call from
ProjectRestrictNode.generateMinion() for the PRN that once was the FromSubquery
(mentioned earlier). At this stage the RCL for *both* queries look like:
RC (resultset# = 3)
| .expression=
VCN
| .sourceColumn =
RC (resultset# = -1)
|
CR
|
... (into base table)
However
- in the working query, the correlate flag is false for the base table columns
- in the failing query, the correlate flag is true for the base table columns
This was the only obvious difference I could see, and the correlate flag is
what causes the logic in RCL.generateCore() to stray off on its "wild path".
Looks like I need to investigate why the correlation flag differs between the
two.
> Add support for ROW_NUMBER() window function
> --------------------------------------------
>
> Key: DERBY-2998
> URL: https://issues.apache.org/jira/browse/DERBY-2998
> Project: Derby
> Issue Type: Sub-task
> Components: SQL
> Reporter: Thomas Nielsen
> Assignee: Thomas Nielsen
> Priority: Minor
> Attachments: d2998-10.diff, d2998-10.stat, d2998-11.diff,
> d2998-12.diff, d2998-12.stat, d2998-13.diff, d2998-13.stat, d2998-14.diff,
> d2998-14.stat, d2998-15.diff, d2998-15.stat, d2998-16.diff, d2998-16.stat,
> d2998-4.diff, d2998-4.stat, d2998-5.diff, d2998-5.stat, d2998-6.diff,
> d2998-6.stat, d2998-7.diff, d2998-7.stat, d2998-8.diff, d2998-8.stat,
> d2998-9-derby.log, d2998-9.diff, d2998-9.stat, d2998-doc-1.diff,
> d2998-doc-1.stat, d2998-test.diff, d2998-test.stat, d2998-test2.diff,
> d2998-test2.stat, d2998-test3.diff, d2998-test3.stat, d2998-test4.diff,
> d2998-test4.stat, d2998-test6.diff, d2998-test7.diff
>
>
> As part of implementing the overall OLAP Operations features of SQL
> (DERBY-581), implement the ROW_NUMBER() window function.
> More information about this feature is available at
> http://wiki.apache.org/db-derby/OLAPRowNumber
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