KEEP GOING

https://leetcode.com/problems/tree-node/submissions/ CASE WHEN 사용 ( IN ) SELECT id ,(CASE WHEN p_id IS NULL THEN 'Root' WHEN id IN (SELECT p_id FROM Tree) THEN 'Inner' ELSE 'Leaf' END)AS type FROM Tree ORDER BY id CASE WHEN 사용 ( NOT IN ) SELECT id ,(CASE WHEN p_id IS NULL THEN 'Root' WHEN id NOT IN (SELECT p_id FROM Tree WHERE p_id IS NOT NULL) THEN 'Leaf' ELSE 'Inner' END)AS type FROM Tree ORDE..