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From "Ashish Thusoo (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-556) let hive support theta join
Date Fri, 12 Jun 2009 01:30:07 GMT

    [ https://issues.apache.org/jira/browse/HIVE-556?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12718689#action_12718689
] 

Ashish Thusoo commented on HIVE-556:
------------------------------------

I think with map-side joins this becomes quite easy. How would you do it with a normal map-reduce
join without actually doing a cartesian product at some level?

> let hive support theta join
> ---------------------------
>
>                 Key: HIVE-556
>                 URL: https://issues.apache.org/jira/browse/HIVE-556
>             Project: Hadoop Hive
>          Issue Type: New Feature
>    Affects Versions: 0.4.0
>            Reporter: Min Zhou
>             Fix For: 0.4.0
>
>
> Right now , hive only support equal joins .  Sometimes it's not enough, we must consider
implementing theta joins like
> {code:sql}
> SELECT
>   a.subid, a.id, t.url
> FROM
>   tbl t JOIN aux_tbl a ON t.url rlike a.url_pattern
> WHERE
>   t.dt='20090609'
>   AND a.dt='20090609';
> {code}
> any condition expression following 'ON' is  appropriate.

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