You are viewing a plain text version of this content. The canonical link for it is here.
Posted to derby-dev@db.apache.org by "Stefan Zeiger (JIRA)" <ji...@apache.org> on 2012/08/28 13:38:07 UTC
[jira] [Commented] (DERBY-5911) WHERE condition getting pushed into
sub-query with FETCH
[ https://issues.apache.org/jira/browse/DERBY-5911?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13443082#comment-13443082 ]
Stefan Zeiger commented on DERBY-5911:
--------------------------------------
Note that this attempt at a work-around suffers from the same issue:
select cof_name, price from (
select row_number() over() as rownum, COF_NAME, PRICE from (select * from COFFEES order by COF_NAME) t
) as t where t.rownum <= 2 and t.PRICE < 10
> WHERE condition getting pushed into sub-query with FETCH
> --------------------------------------------------------
>
> Key: DERBY-5911
> URL: https://issues.apache.org/jira/browse/DERBY-5911
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.9.1.0
> Environment: Tested with Derby 10.9.1.0 on Windows 7 x64, Java 1.6.0_27-b07 server
> Reporter: Stefan Zeiger
>
> Derby pushes query conditions down into subqueries with FETCH limits, thus creating wrong results. Take the following snippet:
> CREATE TABLE COFFEES (COF_NAME VARCHAR(254),PRICE INTEGER);
>
> INSERT INTO COFFEES (COF_NAME,PRICE) VALUES ('Colombian', 5);
> INSERT INTO COFFEES (COF_NAME,PRICE) VALUES ('French_Roast', 5);
> INSERT INTO COFFEES (COF_NAME,PRICE) VALUES ('Colombian_Decaf', 20);
>
> select COF_NAME, PRICE from COFFEES order by COF_NAME fetch next 2 rows only;
>
> select * from (
> select COF_NAME, PRICE from COFFEES order by COF_NAME fetch next 2 rows only
> ) t where t.PRICE < 10;
> The first query correctly returns the rows (Colombian,5), (Colombian_Decaf,20).
> The second query (which filters the result of the first one) returns (Colombian,5), (French_Roast,5). The row (French_Roast,5) should not be there since it is not a result of the first query. It shows up because (supposedly) the filter condition has been evaluated before the fetch limit.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira