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From "Min Zhou (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-556) let hive support theta join
Date Fri, 12 Jun 2009 02:34:07 GMT

    [ https://issues.apache.org/jira/browse/HIVE-556?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12718699#action_12718699
] 

Min Zhou commented on HIVE-556:
-------------------------------

@Ashish
I agree with you, map-side joins is okay. however,  it doesnot support theta joins right now.
 we used to load aux tables into the memory of each map node,  scan major tables and do our
joins. 

> 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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