Question
What are the relation operations in Pig? Explain any two with examples?
Answers
The relational operations in Pig:
foreach, order by, filters, group, distinct, join, limit.foreach: It takes a set of expressions and applies them to all records in the data pipeline to the next operator.A =LOAD ‘input’ as (emp_name :charrarray, emp_id : long, emp_add : chararray, phone : chararray, preferences : map [] );B = foreach A generate emp_name, emp_id;Filters: It contains a predicate and it allows us to select which records will be retained in our data pipeline.
Syntax: alias = FILTER alias BY expression;
Alias indicates the name of the relation, By indicates required keyword and the expression has Boolean.
Example: M = FILTER N BY F5 == 4;   Your Comment




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