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https://issues.apache.org/jira/browse/HIVE-24957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17313012#comment-17313012
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Stamatis Zampetakis commented on HIVE-24957:
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{quote}it seems to me that we could avoid this issue by materializing the
coalesced value before the correlated subq:
{quote}
[~kgyrtkirk] This is what I thought as well :) I am building a prototype along
this idea.
> Wrong results when subquery has COALESCE in correlation predicate
> -----------------------------------------------------------------
>
> Key: HIVE-24957
> URL: https://issues.apache.org/jira/browse/HIVE-24957
> Project: Hive
> Issue Type: Bug
> Affects Versions: 4.0.0
> Reporter: Stamatis Zampetakis
> Assignee: Stamatis Zampetakis
> Priority: Major
>
> Consider the following example:
> {code:sql}
> create table author (
> a_authorkey int,
> a_name varchar(50));
> create table book (
> b_bookkey int,
> b_title varchar(50),
> b_authorkey int);
> insert into author values (10, 'Victor Hugo');
> insert into author values (20, 'Alexandre Dumas');
> insert into author values (300, 'UNKNOWN');
> insert into book values (1, 'Les Miserables', 10);
> insert into book values (2, 'The Count of Monte Cristo', 20);
> insert into book values (3, 'Men Without Women', 30);
> insert into book values (4, 'Odyssey', null);
> select b.b_title
> from book b
> where exists
> (select a_authorkey
> from author a
> where coalesce(b.b_authorkey, 300) = a.a_authorkey);
> {code}
> *Expected results*
> ||B_TITLE||
> |Les Miserables|
> |The Count of Monte Cristo|
> |Odyssey|
> *Actual results*
> ||B_TITLE||
> |Les Miserables|
> |The Count of Monte Cristo|
> {{Odyssey}} is missing from the result set and it shouldn't since with the
> application of COALESCE operator it should match with the UNKNOWN author.
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