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Posted to dev@pig.apache.org by "Olga Natkovich (JIRA)" <ji...@apache.org> on 2008/09/04 03:09:44 UTC

[jira] Assigned: (PIG-361) JOIN and cogroup should handle NULLs correctly

     [ https://issues.apache.org/jira/browse/PIG-361?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Olga Natkovich reassigned PIG-361:
----------------------------------

    Assignee: Shravan Matthur Narayanamurthy  (was: Alan Gates)

Shravan, could you take a look plaese. 

I think we want to preserve SQL semantics here:

JOIN / INNER COGROUP - throws away all NULLs
OUTER COGROUP + flatten with bincond  simulates outer joins where missing data is padded by NULLs and  nulls are assumed to be all different - never multiplied.

> JOIN and cogroup should handle NULLs correctly
> ----------------------------------------------
>
>                 Key: PIG-361
>                 URL: https://issues.apache.org/jira/browse/PIG-361
>             Project: Pig
>          Issue Type: Sub-task
>    Affects Versions: types_branch
>            Reporter: Pradeep Kamath
>            Assignee: Shravan Matthur Narayanamurthy
>             Fix For: types_branch
>
>
> JOIN should follow SQL semantics .i.e if the join key is a null or part of the join key is null in the first table, it should not join with similar keys in the second table.
> Cogroup should coalesce all NULL key rows into one group.

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