The GROUP operator is used to group the data in one or more relations. It collects the data having the same key.
grunt> group_data = GROUP student_details by age;
grunt> Describe group_data;
grunt> Illustrate group_data;
Grouping by Multiple Columns
grunt> group_multiple = GROUP student_details by (age, city);
grunt> group_all = GROUP student_details All;
grunt> Dump group_all;