The following data and task is from the PostgreSQL Exercises created by Alisdair Owens. More specifically: https://pgexercises.com/questions/joins/self2.html
The dataset was copied from Github, modified slightly and then converted into a CSV of the original to import into a Jupyter Notebook.
When doing the above exercise I was not getting the correct results with my solution.
Once I saw the solution provided it became a little more clear on what I had done wrong. I've replicated the exercise here so that I could delve into it further and maybe help others with Self joining tables and the LEFT JOIN clause.