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https://issues.apache.org/jira/browse/DERBY-6008?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13526258#comment-13526258
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Knut Anders Hatlen commented on DERBY-6008:
-------------------------------------------
Dag, I applied the "c" version of the patch and ran some tests in ij. This
particular sequence didn't look quite right to me:
ij version 10.10
ij> connect 'jdbc:derby:memory:db;create=true';
ij> create table countries(name varchar(20), population int, area int);
0 rows inserted/updated/deleted
ij> insert into countries values
('Norway', 5033675, 385252),
('Sweden', 9540065, 449964),
('Denmark', 5580413, 42894),
('Iceland', 320060, 103001),
('Liechtenstein', 36281, 160);
5 rows inserted/updated/deleted
ij> SELECT NAME FROM COUNTRIES ORDER BY POPULATION DESC FETCH FIRST 2 ROWS ONLY;
NAME
--------------------
Sweden
Denmark
2 rows selected
ij> SELECT NAME FROM COUNTRIES ORDER BY AREA DESC FETCH FIRST 2 ROWS ONLY;
NAME
--------------------
Sweden
Norway
2 rows selected
ij> (SELECT NAME FROM COUNTRIES ORDER BY POPULATION DESC FETCH FIRST 2 ROWS
ONLY)
INTERSECT
(SELECT NAME FROM COUNTRIES ORDER BY AREA DESC FETCH FIRST 2 ROWS ONLY);
NAME
--------------------
Denmark
Iceland
2 rows selected
The intersection of ('Sweden', 'Denmark') and ('Sweden', 'Norway') should be
('Sweden') and not ('Denmark', 'Iceland').
> Allow ORDER BY and FETCH/OFFSET in set operands
> -----------------------------------------------
>
> Key: DERBY-6008
> URL: https://issues.apache.org/jira/browse/DERBY-6008
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Reporter: Dag H. Wanvik
> Assignee: Dag H. Wanvik
> Attachments: derby-6008-a.diff, derby-6008-a.stat, derby-6008-b.diff,
> derby-6008-b.stat, derby-6008-c.diff, derby-6008-c.stat
>
>
> Currently, Derby doesn't allow ORDER BY nested in a set operand, e.g. in the
> following construct:
> (select i from t1 order by j offset 1 row) union
> (select i from t2 order by j desc offset 2 rows)
> This is allowed by the standard, as far as I can understand, cf. this quote
> from section 7.12 in SQL 2011:
> <query expression body> ::=
> <query term>
> | <query expression body> UNION [ ALL | DISTINCT ]
> [ <corresponding spec> ] <query term>
> | <query expression body> EXCEPT [ ALL | DISTINCT ]
> [ <corresponding spec> ] <query term>
> <query term> ::=
> <query primary>
> | <query term> INTERSECT [ ALL | DISTINCT ]
> [ <corresponding spec> ] <query primary>
> <query primary> ::=
> <simple table>
> | <left paren> <query expression body>
> [ <order by clause> ] [ <result offset clause> ] [ <fetch first clause>
> ] <right paren>
> I.e. the left paren chooses the second alternative in the production for
> <query primary>.
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