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Hive >> mail # user >> Cross join in Hive.


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Re: Cross join in Hive.
you could probably just say (1 = 1) in the on clause for the join.

set hive.mapred.mode=nonstrict;
select ... from T1 join T2 on (1 = 1);

Ashish

On May 1, 2011, at 10:27 PM, Raghunath, Ranjith wrote:

Forgot to mention....the condition for the inner join should be the column set to 1 in the first table to be equal to the same column in the other table.

Thanks,
Ranjith

________________________________
From: Raghunath, Ranjith <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
To: '[EMAIL PROTECTED]<mailto:'[EMAIL PROTECTED]>' <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Sent: Mon May 02 00:21:57 2011
Subject: Re: Cross join in Hive.

I haven't tested this out but plan to in 6 hours. Add an extra column and set it to 1 in both tables. Perform an inner join between the two tables.

Thanks,
Ranjith

________________________________
From: Abhinov Agarwal <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
To: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Sent: Sun May 01 22:50:34 2011
Subject: Cross join in Hive.

Hi,

I need to take a cross join of a big table with itself, is it possible to do it using Hive ?
E.g.

Set :
1
2
3

Result :
1,1
1,2
1,3
2,1
2,2
2,3
3,1
3,2
3,3

This would also do :
1,2
1,3
2,3

In fact the second one is what I want. I know cross join is not supported in Hive, any other way to obtain this.

Regards,
Abhinav Agarwal

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