# Write your MySQL query statement below
SELECT DISTINCT t1.id, (
CASE
WHEN t1.p_id IS NULL THEN 'Root'
WHEN t1.p_id IS NOT NULL AND t2.id IS NOT NULL THEN 'Inner'
WHEN t1.p_id IS NOT NULL AND t2.id IS NULL THEN 'Leaf'
END
) AS Type
FROM tree t1
LEFT JOIN tree t2
ON t1.id = t2.p_id
#
select id,
(case
when p_id is NULL then 'Root'
when id not in (select a.p_id from tree a) then 'Leaf'
else 'Inner'
end) as Type
from tree
order by id