[GROUP BY/LEVEL2] 조건에 맞는 사원 정보 조회하기 (MySQL)

MySQL

SELECT    
          SUM(SCORE) AS SCORE
        , C.EMP_NO
        , B.EMP_NAME
        , B.POSITION
        , B.EMAIL
FROM HR_DEPARTMENT A, HR_EMPLOYEES B, HR_GRADE C
WHERE A.DEPT_ID = B.DEPT_ID
AND B.EMP_NO = C.EMP_NO
GROUP BY C.EMP_NO
        , B.EMP_NAME
        , B.POSITION
        , B.EMAIL
ORDER BY SCORE DESC
LIMIT 1