Problem Name: Sql -
In this HackerRank Functions in SQL problem solution,
You are given a table, BST, containing two columns: N and P, where N represents the value of a node in Binary Tree, and P is the parent of N.
Write a query to find the node type of Binary Tree ordered by the value of the node. Output one of the following for each node:
- Root: If node is root node.
- Leaf: If node is leaf node.
- Inner: If node is neither root nor leaf node.
1 Leaf 2 Inner 3 Leaf 5 Root 6 Leaf 8 Inner 9 Leaf
The Binary Tree below illustrates the sample:
#1 Code Example with SQL
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SELECT N, CASE WHEN P IS NULL THEN 'Root' WHEN(SELECT COUNT(*) FROM BST WHERE P = A.N) > 0 THEN 'Inner' ELSE 'Leaf' END FROM BST A ORDER BY N;