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Date: Tue, 28 Aug 2007 10:45:13 -0700
From: Alan Gates <gates@yahoo-inc.com>
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To: hadoop-user@lucene.apache.org
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Subject: Re: looking for some help with pig syntax
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I think the following will do what you want.

t1 = load table1 as id, listOfId;
t2 = load table2 as id, f1;
t1a = foreach t1 generate flatten(listOfId); -- flattens the lisOfId 
into a set of ids
b = join t1a by $0, t2 by id; -- join the two together.
c = foreach b generate t2.id, t2.f1; -- project just the ids and f1 entries.

Alan.

Joydeep Sen Sarma wrote:
> Specifically, how can we express this query:
>
>  
>
> Table1 contains: id, (list of ids)
>
> Table2 contains: id, f1
>
>  
>
> Where the Table1:list is a variable length list of foreign key (id) into
> Table2.
>
>  
>
> We would like to join every element of Table1:list with corresponding
> Table2:id. Ie. The final output should of the form:
>
>  
>
> Table3 contains: id, (list of f1)
>
>  
>
> Couldn't quite figure out how to do this - does Pig Latin support nested
> foreach loops? If there's a more appropriate mailing list - please
> re-direct,
>
>  
>
> Thanks,
>
>  
>
> Joydeep
>
>  
>
>  
>
>
>