BIP report to fetch department changes record for employee

Requirement to fetch all the records where department attribute is being changed irrespective of action and action reason for an employee.

For this we are comparing previous and latest record department attribute.

However we are trying to fetch past 3 years data and when comparing the dept change attribute, this is done in an random order and all the previous records are fetched, where it should pull only records with dept change.

(example person has 5 history records and two records dept change performed)

Any suggestions on how to compare the records in an order.