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https://issues.apache.org/jira/browse/DERBY-3634?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dag H. Wanvik updated DERBY-3634:
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Attachment: derby-3634-a.txt
derby-3634-a.stat
derby-3634-a.diff
While looking into the issues logged against the present
ROW_NUMBER/WINDOW functionality (DERBY-3634(1), DERBY-3635(2),
DERBY-4069(3), I was hard pressed to find a way to fix these without
doing a major rewrite.
1) DERBY-3634 Cannot use row_number() in ORDER BY clause
2) DERBY-3635 Cannot build SELECT LIST expressions involving row_number()
3) DERBY-4069 Wrong behavior when ROW_NUMBER is combined with ORDER BY
This patch is a proof-of-concept (not for commit!) for restructuring
the row_number/windowing code, which solves the three issues above and
adds some generality as well.
It does not yet address DERBY-3505 "Current implementation of
ROW_NUMBER() window function does not stop execution once criteria is
met".
For details, see the write-up in derby-3634-a.txt.
The patch adds new tests for the new functionality. Regressions ran cleanly.
> Cannot use row_number() in ORDER BY clause
> ------------------------------------------
>
> Key: DERBY-3634
> URL: https://issues.apache.org/jira/browse/DERBY-3634
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.4.1.3
> Reporter: Rick Hillegas
> Assignee: Dag H. Wanvik
> Attachments: derby-3634-a.diff, derby-3634-a.stat, derby-3634-a.txt
>
>
> The following query works correctly:
> select abs(a), row_number() over ()
> from t
> where a > 100 and a < 111
> order by abs(a)
> I expected the following query to also work, but it raised an exception:
> select abs(a), row_number() over ()
> from t
> where a > 100 and a < 111
> order by row_number() over ()
> This is the error I saw: "ERROR 42X01: Syntax error: Encountered "over" at
> line 5, column 23".
> Here are the reasons why I think that this syntax is supposed to be supported:
> According to my reading of the 2003 SQL spec, the ORDER BY clause should be
> able to sort on any expression in the SELECT list. That includes OLAP
> expressions. I believe this is so because, according to part 2, section 10.10
> (<sort specification>), a <sort key> can be any <value expression> and if you
> follow the grammar for <value expression>, it can resolve to be a <value
> expression primary> (see section 6.3), which can in turn resolve to be a
> <window function>. This reasoning is supported by tracing the hotlinks on the
> following page which lays out the SQL 2003 BNF:
> http://savage.net.au/SQL/sql-2003-2.bnf.html This interpretation is further
> supported by the example of an ORDER BY clause referencing an OLAP expression
> which is provided on page 23 of the introduction to OLAP written by Fred
> Zemke, Krishna Kulkarni, Andy Witkowski, and Bob Lyle:
> www.cse.iitb.ac.in/dbms/Data/Papers-Other/SQL1999/OLAP-99-154r2.pdf
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