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https://issues.apache.org/jira/browse/DERBY-4406?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12858576#action_12858576
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Lily Wei commented on DERBY-4406:
---------------------------------
The detail explanation clearly explains why we are leading toward to not fixing
it. Just out of curiosity, will performance be better if we ordering by RANDOM
or it will pretty much be the same as using correlation names. I am not saying
performance will be better. I just think this is a best time to evaluate the
benefit if we can gain some.
> 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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