Oracle SQL: Display row number for rows grouped by a column

Question

I have the following dataset:

What I would like is for this result:

I've tried using DENSE_RANK but got nowhere fast. I've read through a few stack overflow pages but am now staring at a blank sheet as I can't get anything to work.

Any ideas? Pointers?

EDIT

This seems to be ok so far - any obvious issues?

SELECT Person_id,
    PERSON_NUMBER,
    EFFECTIVE_START_DATE,
    EFFECTIVE_END_DATE,
    ROW_NUMBER() OVER (PARTITION BY Person_id ORDER BY Person_id) YEAH
FROM PER_ALL_PEOPLE_F 

Answer 1

If my assumption is right then you want to fetch the individual person's record in chronological order.

SELECT
    PERSON_ID,
    PERSON_NUMBER,
    EFFECTIVE_START_DATE,
    EFFECTIVE_END_DATE,
    ROW_NUMBER() OVER(
        PARTITION BY PERSON_ID
        ORDER BY
            EFFECTIVE_START_DATE
    ) YEAH
FROM
    <YOUR TABLE>
ORDER BY PERSON_ID, YEAH

Note: I know this table and even worked on it. Please edit your question and remove the table name from your question. It's a bad practice to reveal the table name on the WEB. Column names are fine but not a table name.