Use of Group by

I have data with two fields- Student’s Id and student’s contact number . Each student have multiple contact number so multiple entries are there for each student. I want to have student’s Id and all his contact numbers in one row. Can I use group by to achieve this? If yes ,How?

You can use Group By plugin to achieve this.
In Group By plugin configuration, select StudentID as Group field.
Select ‘Type’ in ‘aggregates’ as “Concatenate strings separated by ,”.
This would group data of each students (1 row for each student) and all contact numbers for that studentID separated by comma would be added in new field.