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Pig >> mail # user >> How to create an empty alias


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Kevin LION 2012-10-18, 16:15
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Re: How to create an empty alias
Sorry, for late response. In case you still need this.
You can try to read from file:/dev/null
This should work for most formats.

2012/10/18 Kevin LION <[EMAIL PROTECTED]>

> Hello,
>
> I've a script which group lot of alias and is doing some operation on it.
> But it can happen that I don't need one of this alias. To don't change my
> code, I would like to create an empty alias. How can I do that ?
>
> Actually my code is like that :
> A = LOAD A AS (id, a1, a2);
> B = LOAD A AS (id, b1, b2);
> C = LOAD A AS (id, c1, c2);
> GROUP = COGROUP A BY id, B BY id, C BY id;
> GROUP2 = FOREACH GROUP GENERATE TOTUPLE(A, B, C) AS ALL;
> OPERATION = FOREACH GROUP2 GENERATE MyUDF(ALL);
>
> And I would like to do something like that :
> A = LOAD A AS (id, a1, a2);
> B = LOAD A AS (id, b1, b2);
> *C = LOAD NULL AS (id, c1, c2); <- Generate an empty alias with column id,
> c1, c2;*
> GROUP = COGROUP A BY id, B BY id, C BY id;
> GROUP2 = FOREACH GROUP GENERATE TOTUPLE(A, B, C) AS ALL;
> OPERATION = FOREACH GROUP2 GENERATE MyUDF(ALL);
>
--
Best regards,
 Vitalii Tymchyshyn
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yogesh dhari 2012-11-07, 18:32
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yogesh dhari 2012-11-08, 03:42
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB