Pig JOIN Operation Explained

In Pig, the JOIN operation is implemented by using the JOIN keyword. By using the JOIN keyword, it is possible to connect two or more datasets together based on specified conditions.

Specifically, the JOIN operation in Pig is accomplished in two stages. Initially, Pig groups each dataset based on the JOIN condition and merges the data records with the same JOIN condition together. Then, Pig performs a Cartesian product operation on these data records to generate the final JOIN result.

The syntax for the JOIN operation in Pig is typically as follows:

result = JOIN dataset1 BY key, dataset2 BY key;

dataset1 and dataset2 are the datasets to be joined, with the key as the condition for the join. The JOIN operation will connect the two datasets based on the specified key and store the result in the result.