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From "Bryan Pendleton (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-2526) Wrong query results due to column ordering in UNION view
Date Mon, 09 Apr 2007 04:10:32 GMT

    [ https://issues.apache.org/jira/browse/DERBY-2526?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12487471

Bryan Pendleton commented on DERBY-2526:

joinClauseTransitiveClosure is examining the two predicates:
    b3.c8 = bvw2.c5
   bvw2.c1 = b4.c7

However, in the second predicate, the ColumnReference for bvw2.c1 has
columnNumber = 5, so joinClauseTransitiveClosure, which matches up
the predicates based on tableNumber and columnNumber, thinks that
this is the predicate
   bvw2.c5 = b4.c7

And, therefore, it computes the transitive closure to include the predicate
   b3.c8 = b4.c7

So next I need to figure out why the columnNumber is wrong in the
leftOperand ColumnReference in the BinaryRelationalOperatorNode for
   bvw2.c1 = b4.c7

> Wrong query results due to column ordering in UNION view
> --------------------------------------------------------
>                 Key: DERBY-2526
>                 URL: https://issues.apache.org/jira/browse/DERBY-2526
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions:,,,
>            Reporter: Bryan Pendleton
>         Assigned To: Bryan Pendleton
>         Attachments: badQuery.log, derby-2526.sql, goodQuery.log
> I think both select statements in the attached repro script should return 1 row, but
in fact the first statement returns 1 row and the second returns zero rows.
> The only difference between the two statements is that the columns in the UNION view
are listed in a different order (bvw vs. bvw2).
> This seems like a bug to me; the order of the columns in the view definition shouldn't
matter, should it? 
> As Army noted on the derby-dev list, the fact that this reproduces with 10.0 means that
it is not caused by some of the 10.2 optimizer changes. Something else is going wrong.

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