[프로그래머스/SQL 고득점 Kit] 조건에 부합하는 중고거래 댓글 조회하기

💪문제
USED_GOODS_BOARD와 USED_GOODS_REPLY 테이블에서 2022년 10월에 작성된 게시글 제목, 게시글 ID, 댓글 ID, 댓글 작성자 ID, 댓글 내용, 댓글 작성일을 조회하는 SQL문을 작성해주세요. 결과는 댓글 작성일을 기준으로 오름차순 정렬해주시고, 댓글 작성일이 같다면 게시글 제목을 기준으로 오름차순 정렬해주세요.

 

프로그래머스

 

 

 

💪 나의 정답

SELECT a.TITLE, a.BOARD_ID, b.REPLY_ID, b.WRITER_ID, b.CONTENTS, DATE_FORMAT(b.CREATED_DATE, '%Y-%m-%d') AS 'CREATED_DATE'
FROM USED_GOODS_BOARD AS a
INNER JOIN USED_GOODS_REPLY AS b
# ON a.WRITER_ID = b.WRITER_ID 
ON a.BOARD_ID = b.BOARD_ID
WHERE DATE_FORMAT(a.CREATED_DATE, '%Y-%m') = '2022-10'
ORDER BY b.CREATED_DATE ASC, a.TITLE;

 

 

💪 다른 정답

<LIKE 활용>

SELECT B.TITLE, B.BOARD_ID, R.REPLY_ID, R.WRITER_ID, R.CONTENTS, 
DATE_FORMAT(R.CREATED_DATE,"%Y-%m-%d") AS CREATED_DATE
FROM USED_GOODS_BOARD AS B  
INNER JOIN USED_GOODS_REPLY AS R 
ON B.BOARD_ID = R.BOARD_ID 
-- WHERE MONTH(B.CREATED_DATE) = 10
WHERE B.CREATED_DATE like '2022-10%'
ORDER BY R.CREATED_DATE ASC,  B.TITLE ASC;

 

<SUBSTR 활용>

SELECT B.TITLE, B.BOARD_ID, R.REPLY_ID, R.WRITER_ID, R.CONTENTS, 
DATE_FORMAT(R.CREATED_DATE,"%Y-%m-%d") AS CREATED_DATE
FROM USED_GOODS_BOARD AS B  
INNER JOIN USED_GOODS_REPLY AS R 
ON B.BOARD_ID = R.BOARD_ID 
-- WHERE MONTH(B.CREATED_DATE) = 10
-- WHERE B.CREATED_DATE like '2022-10%'
-- WHERE DATE_FORMAT(B.CREATED_DATE, '%Y-%m') = '2022-10'
WHERE  SUBSTR(B.CREATED_DATE,1,7) = '2022-10'
ORDER BY R.CREATED_DATE ASC,  B.TITLE ASC;

 

<BETWEEN 활용>

SELECT B.TITLE, B.BOARD_ID, R.REPLY_ID, R.WRITER_ID, R.CONTENTS, 
DATE_FORMAT(R.CREATED_DATE,"%Y-%m-%d") AS CREATED_DATE
FROM USED_GOODS_BOARD AS B  
INNER JOIN USED_GOODS_REPLY AS R 
ON B.BOARD_ID = R.BOARD_ID 
-- WHERE MONTH(B.CREATED_DATE) = 10
-- WHERE B.CREATED_DATE like '2022-10%'
-- WHERE DATE_FORMAT(B.CREATED_DATE, '%Y-%m') = '2022-10'
-- WHERE SUBSTR(B.CREATED_DATE,1,7) = '2022-10'
WHERE B.CREATED_DATE BETWEEN ('2022-10-01') AND ('2022-10-31')
ORDER BY R.CREATED_DATE ASC,  B.TITLE ASC;

 

 

 

💪 배운 점

- 문제를 꼼꼼히 읽어야 함을 느꼈다.

- LIKE문의 활용, SUBSTR의 활용, BETWEEN의 활용과 같은 다양한 구문을 활용법을 배웠다.

 

 

 

💪 마치면서

다음에는 다른 문제로 찾아뵙겠습니다!

안녕 :))