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From "Thomas Nielsen (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-2998) Add support for ROW_NUMBER() window function
Date Tue, 26 Feb 2008 14:38:51 GMT

    [ https://issues.apache.org/jira/browse/DERBY-2998?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12572498#action_12572498
] 

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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