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 as node_type
from bst
order by n;

SELECT 
N,
CASE 
WHEN P IS NULL THEN "Root"
WHEN N IN (SELECT P from BST WHERE P IS NOT NULL ) then "Inner"
ELSE "Leaf"
END AS Type
FROM BST
ORDER BY N;

/*
Enter your query here.
Condition 1: Root node is the node does not have a parent node P = NULL
Condition 2: Inner nodes have a parent node (P IS NOT NULL) AND are parent to other nodes (N in P)
Condition 3: Else Leaf
*/

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