데이터의 최댓값을 구하는 함수
SELECT MAX(SCORE) AS MAX_SCORE FROM SQLD;

SELECT student_name,
subject,
score,
MAX(score) OVER(PARTITION BY subject) as max_score
FROM sqld
ORDER BY score;

SELECT student_name,
subject,
score
FROM (
SELECT student_name,
subject,
score,
MAX(score) OVER(PARTITION BY subject) as max_score
FROM sqld) as drived_table
WHERE score = max_score;
(as drived_table 이 부분이 없었을 때 MySQL에서는 에러가 발생했었다.)
