Question on challenge

[yaravind]

Thank you for the example. Learned quite a bit! I have following questions if you can help!

1. Why do we have to sort the department DF? What advantage does it give?
2. Why to sort in this specific order: 'id, 'assigned_date, 'company_id, 'factory_id' ?
3. What is the intent of the query in the code? Count of all users whose joined a department on the same day their birth date?

[vitalyte]

@yaravind you are welcome. I think our detail description in blog could help you in research https://dataengi.com/2019/02/06/spark-data-skew-problem/