[프로그래머스] SQL 고득점 kit(물고기 종류 별 잡은 수 구하기)

문제

FISH_NAME_INFO에서 물고기의 종류 별 물고기의 이름과 잡은 수를 출력하는 SQL문을 작성해주세요.
물고기의 이름 컬럼명은 FISH_NAME, 잡은 수 컬럼명은 FISH_COUNT로 해주세요.
결과는 잡은 수 기준으로 내림차순 정렬해주세요.

 

내 풀이(오답)

 

SELECT COUNT(*) AS FISH_COUNT, B.FISH_NAME
FROM FISH_INFO AS A 
INNER JOIN FISH_NAME_INFO AS B
ON A.FISH_TYPE = B.FISH_TYPE
GROUP BY A.FISH_TYPE
ORDER BY FISH_COUNT DESC;

• GROUP BY A.FISH_TYPE를 사용할 때 선택한 열 B.FISH_NAME도 GROUP BY 절에 포함되어야 함

 

정답

 

SELECT COUNT(*) AS FISH_COUNT, B.FISH_NAME
FROM FISH_INFO AS A 
INNER JOIN FISH_NAME_INFO AS B
ON A.FISH_TYPE = B.FISH_TYPE
GROUP BY A.FISH_TYPE, B.FISH_NAME
ORDER BY FISH_COUNT DESC;