select  a.n, max(
    case when b.n is null and c.n is not null then
            'Root'
         when b.n is not null and c.n is null then
            'Leaf'
         else
            'Inner'
    end )
from bst a
left join bst b on a.p = b.n
left join bst c on c.p = a.n
group by a.n
order by a.n ;