How to get min and max date in SQL since branch the branch code changed

I have table as below. I'm using plsql

And I want to find min and max dates each branch changes. I partioned based on branch_code and emp_ID but I couldn't what I want.

And this is what I want;

I want to find min and max date when branch changed. And also calculate time between min and max date.

This is a gaps and islands problem, and we can use the difference in row numbers method here.

WITH cte AS (
    SELECT t.*, ROW_NUMBER() OVER (PARTITION BY ID
                                   ORDER BY StartDate) rn1,
                ROW_NUMBER() OVER (PARTITION BY ID, BranchCode
                                   ORDER BY StartDate) rn2
    FROM yourTable t
)

SELECT
    ID,
    BranchCode,
    MIN(StartDate) AS MinStartDate,
    MAX(FinishDate) AS MaxFinishDate
FROM cte
GROUP BY
    ID,
    BranchCode,
    rn1 - rn2
ORDER BY
    ID,
    MIN(StartDate);

The basic idea here is to form a pseudo group column defined by the ID, BranchCode, and a difference in row numbers sequence. Then, all we need to is aggregate and take the appropriate min/max.