[LeetCode] 608. Tree Node

 

 

[문제]

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[MySQL]

WITH node AS (
    SELECT t1.*
        , t2.id AS c_id
    FROM Tree AS t1
        LEFT JOIN Tree AS t2 ON t1.id = t2.p_id
)

SELECT DISTINCT id
     , CASE WHEN p_id IS NULL THEN 'Root'
            WHEN c_id IS NULL THEN 'Leaf'
            ELSE 'Inner'
        END AS type
FROM node