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https://issues.apache.org/jira/browse/TRAFODION-3296?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16813816#comment-16813816
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David Wayne Birdsall commented on TRAFODION-3296:
-------------------------------------------------
Earlier fixes to problems in this area include Jira TRAFODION-2969, which fixed
the case where there is no ORDER BY, and Jira TRAFODION-3025, which attempted
to fix one flavor of the [first n] + ORDER BY problem. Unfortunately, those
fixes do not address the case given in this JIRA.
> Subquery with [first n] + ORDER BY gives wrong answer
> -----------------------------------------------------
>
> Key: TRAFODION-3296
> URL: https://issues.apache.org/jira/browse/TRAFODION-3296
> Project: Apache Trafodion
> Issue Type: Bug
> Reporter: David Wayne Birdsall
> Assignee: David Wayne Birdsall
> Priority: Major
>
> The following test script illustrates the problem:
> {quote}?section setup
> drop table if exists t1;
> drop table if exists t2;
> create table t1 (val integer);
> create table t2 (val integer);
> insert into t1 values(994707150),(1923979352),(-1865644273);
> insert into t2 select * from t1;
> ?section testit
> select [first 1] val from t2 order by val;
> prepare xx from select val from t1 where val in (select [first 1] val from t2
> order by val);
> explain options 'f' xx;
> -- should return -1865644273, but returns something different
> execute xx;
> {quote}
> When run, the script shows:
> {quote}>>?section testit
> >>
> >>select [first 1] val from t2 order by val;
> VAL
> -----------
> -1865644273
> --- 1 row(s) selected.
> >>
> >>prepare xx from select val from t1 where val in (select [first 1] val from
> >>t2 order by val);
> --- SQL command prepared.
> >>
> >>explain options 'f' xx;
> LC RC OP OPERATOR OPT DESCRIPTION CARD
> ---- ---- ---- -------------------- -------- -------------------- ---------
> 5 . 6 root 1.00E+002
> 3 4 5 nested_join 1.00E+002
> . . 4 trafodion_scan T1 1.00E+002
> 2 . 3 hash_groupby 1.00E+000
> 1 . 2 firstn 1.00E+000
> . . 1 trafodion_scan T2 1.00E+002
> --- SQL operation complete.
> >>
> >>-- should return -1865644273, but returns something different
> >>execute xx;
> VAL
> -----------
> 994707150
> --- 1 row(s) selected.
> >>
> {quote}
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