Apache Pig - Cross Operator


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The CROSS operator computes the cross-product of two or more relations. This chapter explains with example how to use the cross operator in Pig Latin.

Syntax

Given below is the syntax of the CROSS operator.

grunt> Relation3_name = CROSS Relation1_name, Relation2_name;

Example

Assume that we have two files namely customers.txt and orders.txt in the /pig_data/ directory of HDFS as shown below.

customers.txt

1,Ramesh,32,Ahmedabad,2000.00
2,Khilan,25,Delhi,1500.00
3,kaushik,23,Kota,2000.00
4,Chaitali,25,Mumbai,6500.00
5,Hardik,27,Bhopal,8500.00
6,Komal,22,MP,4500.00
7,Muffy,24,Indore,10000.00

orders.txt

102,2009-10-08 00:00:00,3,3000
100,2009-10-08 00:00:00,3,1500
101,2009-11-20 00:00:00,2,1560
103,2008-05-20 00:00:00,4,2060

And we have loaded these two files into Pig with the relations customers and orders as shown below.

grunt> customers = LOAD 'hdfs://localhost:9000/pig_data/customers.txt' USING PigStorage(',')
   as (id:int, name:chararray, age:int, address:chararray, salary:int);
  
grunt> orders = LOAD 'hdfs://localhost:9000/pig_data/orders.txt' USING PigStorage(',')
   as (oid:int, date:chararray, customer_id:int, amount:int);

Let us now get the cross-product of these two relations using the cross operator on these two relations as shown below.

grunt> cross_data = CROSS customers, orders;

Verification

Verify the relation cross_data using the DUMP operator as shown below.

grunt> Dump cross_data;

Output

It will produce the following output, displaying the contents of the relation cross_data.

(7,Muffy,24,Indore,10000,103,2008-05-20 00:00:00,4,2060) 
(7,Muffy,24,Indore,10000,101,2009-11-20 00:00:00,2,1560) 
(7,Muffy,24,Indore,10000,100,2009-10-08 00:00:00,3,1500) 
(7,Muffy,24,Indore,10000,102,2009-10-08 00:00:00,3,3000) 
(6,Komal,22,MP,4500,103,2008-05-20 00:00:00,4,2060) 
(6,Komal,22,MP,4500,101,2009-11-20 00:00:00,2,1560) 
(6,Komal,22,MP,4500,100,2009-10-08 00:00:00,3,1500) 
(6,Komal,22,MP,4500,102,2009-10-08 00:00:00,3,3000) 
(5,Hardik,27,Bhopal,8500,103,2008-05-20 00:00:00,4,2060) 
(5,Hardik,27,Bhopal,8500,101,2009-11-20 00:00:00,2,1560) 
(5,Hardik,27,Bhopal,8500,100,2009-10-08 00:00:00,3,1500) 
(5,Hardik,27,Bhopal,8500,102,2009-10-08 00:00:00,3,3000) 
(4,Chaitali,25,Mumbai,6500,103,2008-05-20 00:00:00,4,2060) 
(4,Chaitali,25,Mumbai,6500,101,2009-20 00:00:00,4,2060) 
(2,Khilan,25,Delhi,1500,101,2009-11-20 00:00:00,2,1560) 
(2,Khilan,25,Delhi,1500,100,2009-10-08 00:00:00,3,1500) 
(2,Khilan,25,Delhi,1500,102,2009-10-08 00:00:00,3,3000) 
(1,Ramesh,32,Ahmedabad,2000,103,2008-05-20 00:00:00,4,2060) 
(1,Ramesh,32,Ahmedabad,2000,101,2009-11-20 00:00:00,2,1560) 
(1,Ramesh,32,Ahmedabad,2000,100,2009-10-08 00:00:00,3,1500) 
(1,Ramesh,32,Ahmedabad,2000,102,2009-10-08 00:00:00,3,3000)-11-20 00:00:00,2,1560) 
(4,Chaitali,25,Mumbai,6500,100,2009-10-08 00:00:00,3,1500) 
(4,Chaitali,25,Mumbai,6500,102,2009-10-08 00:00:00,3,3000) 
(3,kaushik,23,Kota,2000,103,2008-05-20 00:00:00,4,2060) 
(3,kaushik,23,Kota,2000,101,2009-11-20 00:00:00,2,1560) 
(3,kaushik,23,Kota,2000,100,2009-10-08 00:00:00,3,1500) 
(3,kaushik,23,Kota,2000,102,2009-10-08 00:00:00,3,3000) 
(2,Khilan,25,Delhi,1500,103,2008-05-20 00:00:00,4,2060) 
(2,Khilan,25,Delhi,1500,101,2009-11-20 00:00:00,2,1560) 
(2,Khilan,25,Delhi,1500,100,2009-10-08 00:00:00,3,1500)
(2,Khilan,25,Delhi,1500,102,2009-10-08 00:00:00,3,3000) 
(1,Ramesh,32,Ahmedabad,2000,103,2008-05-20 00:00:00,4,2060) 
(1,Ramesh,32,Ahmedabad,2000,101,2009-11-20 00:00:00,2,1560) 
(1,Ramesh,32,Ahmedabad,2000,100,2009-10-08 00:00:00,3,1500) 
(1,Ramesh,32,Ahmedabad,2000,102,2009-10-08 00:00:00,3,3000)  

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