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Posted to derby-dev@db.apache.org by "C.S. Nirmal J. Fernando (JIRA)" <ji...@apache.org> on 2010/04/02 05:10:27 UTC
[jira] Commented: (DERBY-4406) Wrong order when using ORDER BY on
non-deterministic function
[ https://issues.apache.org/jira/browse/DERBY-4406?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12852678#action_12852678 ]
C.S. Nirmal J. Fernando commented on DERBY-4406:
------------------------------------------------
Hi,
In OrderByColumn class at bindOrderByColumn(ResultSetNode target, OrderByList oblist) method, the parameter oblist (OrderByList ) should contain the random() expression if we queried "select random() from t order by random();". So, can someone help me to check whether this oblist contains random()? I tried to print it in the console, by using oblist.elementAt(i).toString() and several different statements, but not successful.
Thanks !!
> Wrong order when using ORDER BY on non-deterministic function
> -------------------------------------------------------------
>
> Key: DERBY-4406
> URL: https://issues.apache.org/jira/browse/DERBY-4406
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.5.3.0, 10.6.0.0
> Reporter: Knut Anders Hatlen
> Assignee: C.S. Nirmal J. Fernando
>
> If I read the SQL standard correctly, a statement such as "select random() as r from t order by random()" should be treated as "select random() as r from t order by r". Derby does however generate a second, hidden random() column by which the rows are ordered.
> ij> create table t(x int);
> 0 rows inserted/updated/deleted
> ij> insert into t values 1,2,3,4,5;
> 5 rows inserted/updated/deleted
> ij> -- wrong result, not ordered by r
> ij> select random() as r from t order by random();
> R
> ----------------------
> 0.1285512465366495
> 0.5116860880915798
> 0.21060042130229073
> 0.2506706923680875
> 0.6378857329935494
> 5 rows selected
> ij> -- correct result, ordered by r
> ij> select random() as r from t order by r;
> R
> ----------------------
> 0.0749025910679918
> 0.07694931688380491
> 0.1724114605785414
> 0.2268758969382877
> 0.31900450349277965
> 5 rows selected
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