SELECT DISTINCT N , 'Leaf' FROM BST WHERE N NOT IN (SELECT P FROM BST WHERE P IS NOT NULL) UNION ALL SELECT DISTINCT N , 'Root' FROM BST WHERE P is null UNION ALL SELECT DISTINCT N , 'Inner' FROM BST WHERE N IN (SELECT P FROM BST WHERE P IS NOT NULL) AND P IS NOT NULL ORDER BY N

SELECT N, CASE WHEN P IS NULL THEN 'Root' WHEN N NOT IN (SELECT DISTINCT P FROM BST WHERE P IS NOT NULL) THEN 'Leaf' ELSE 'Inner' END AS NodeType FROM BST ORDER BY N;

select N, CASE WHEN P is null THEN 'Root' WHEN N not in (select P from BST where p is not null) THEN 'Leaf' ELSE 'Inner' END from BST order by N

select n, case when p is null then "Root" when n in (Select p from bst) then "Inner" else "Leaf" end from bst order by n

If you’re curious about the process of Swiss company formation, this guide is worth your time. I liked that it didn’t just list requirements, but also gave context — like why certain rules exist and how they compare to other European countries. It even touches on practical things like opening a corporate bank account. After reading, I feel like I could have an informed conversation with a Swiss lawyer or advisor without sounding clueless. That’s a win in my book.