[LeetCode/SQL] 2356. Number of Unique Subjects Taught by Each Teacher

[LeetCode/SQL]

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📌 2356. Number of Unique Subjects Taught by Each Teacher

문제

풀이

선생님별 가르치는 과목의 수를 출력하라 

방법

SELECT teacher_id,
       COUNT(DISTINCT subject_id) AS cnt
FROM Teacher
GROUP BY teacher_id