The very basics
Infinite looping
Processing trees with recursive CTE
Processing graphs with recursive CTE


Quite impressive, right? We'll now help you construct the query step-by-step so that you understand how it works.


In the first step, we'll show information about the boss. It is the only person in the table that has a NULL superior_id. For that person, show the id, first_name, last_name, superior_id, and the last column called path with 'Boss' inside.

Stuck? Here's a hint!

Remember that you can check whether the value is NULL using

WHERE column_name IS NULL