[MySQL][Lv. 2] ROOT 아이템 구하기 ✨

1. 풀이

SELECT A.ITEM_ID, A.ITEM_NAME
FROM ITEM_INFO A
JOIN ITEM_TREE B
    ON A.ITEM_ID = B.ITEM_ID
WHERE B.PARENT_ITEM_ID IS NULL
ORDER BY ITEM_ID ASC;