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Posted to dev@hive.apache.org by "Matt Tucker (JIRA)" <ji...@apache.org> on 2013/12/12 18:36:07 UTC
[jira] [Commented] (HIVE-5555) Support alternate join syntax:
joining conditions in where clause; also pushdown qualifying join
conditions
[ https://issues.apache.org/jira/browse/HIVE-5555?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13846481#comment-13846481 ]
Matt Tucker commented on HIVE-5555:
-----------------------------------
Does this also allow for SQL-89 style joins?
{noformat}
explain select *
from part p1, part p2, part p3
where p1.p_name = p2.p_name and p2.p_name = p3.p_name;
{noformat}
> Support alternate join syntax: joining conditions in where clause; also pushdown qualifying join conditions
> ------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-5555
> URL: https://issues.apache.org/jira/browse/HIVE-5555
> Project: Hive
> Issue Type: Bug
> Components: Query Processor
> Reporter: Harish Butani
> Assignee: Harish Butani
> Attachments: AlternativeJoinSyntax.pdf
>
>
> Certain tools still generate `old style' Join queries where the join
> condition is in the Where clause. A related set of issues that can
> be addressed is that of pushing forward joining conditions;
> in a manner similar to the Predicate Pushdown feature of Hive.
> For e.g. these queries can have join conditions pushed down:
> {noformat}
> - query 1, push join predicate from 2nd join to 1st
> explain select *
> from part p1 join part p2 join part p3 on p1.p_name = p2.p_name and p2.p_name = p3.p_name;
> - query 2
> explain select *
> from part p1 join part p2 join part p3
> where p1.p_name = p2.p_name and p2.p_name = p3.p_name;
> {noformat}
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