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Posted to dev@hive.apache.org by "Harish Butani (JIRA)" <ji...@apache.org> on 2013/10/16 02:51:41 UTC
[jira] [Created] (HIVE-5555) Support alternate join syntax: joining
conditions in where clause; also pushdown qualifying join conditions
Harish Butani created HIVE-5555:
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Summary: 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
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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