문제코드SELECT a.ID, COUNT(b.ID) AS CHILD_COUNTFROM ECOLI_DATA a LEFT JOIN ECOLI_DATA b ON a.ID = b.PARENT_IDGROUP BY a.IDORDER BY a.ID; 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/lessons/299305

문제코드SELECT ITEM_INFO.ITEM_ID, ITEM_INFO.ITEM_NAME, ITEM_INFO.RARITYFROM ITEM_INFO JOIN ITEM_TREE ON ITEM_INFO.ITEM_ID = ITEM_TREE.ITEM_IDWHERE ITEM_TREE.ITEM_ID NOT IN (SELECT DISTINCT PARENT_ITEM_ID FROM ITEM_TREE WHERE PARENT_ITEM_ID IS NOT NULL)ORDER BY ITEM_INFO.ITEM_ID DESC; 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/lessons/273712

문제코드SELECT COUNT(ID) AS FISH_COUNT,MAX(LENGTH) AS MAX_LENGTH, FISH_TYPEFROM FISH_INFOGROUP BY FISH_TYPEHAVING AVG(CASE WHEN LENGTH IS NULL OR LENGTH 10 THEN LENGTH END) >= 33ORDER BY FISH_TYPE; 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/lessons/298519

문제코드SELECT MONTH(START_DATE) AS MONTH, CAR_ID, COUNT(START_DATE) AS RECORDSFROM CAR_RENTAL_COMPANY_RENTAL_HISTORYWHERE START_DATE BETWEEN '2022-08-01' AND '2022-10-31'AND CAR_ID IN ( SELECT CAR_ID FROM CAR_RENTAL_COMPANY_RENTAL_HISTORY WHERE START_DATE BETWEEN '2022-08-01' AND '2022-10-31' GROUP BY CAR_ID HAVING COUNT(START_DATE) >= 5)GROUP BY MONTH(START_DATE), CAR_IDORDER BY MO..

문제코드SELECT ID, NAME, HOST_IDFROM PLACESWHERE HOST_ID IN (SELECT HOST_ID FROM PLACES GROUP BY HOST_ID HAVING COUNT(NAME) >= 2)ORDER BY ID; 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/lessons/77487

문제코드SELECT CONCAT('/home/grep/src/', UGB.BOARD_ID, '/', UGF.FILE_ID, UGF.FILE_NAME, UGF.FILE_EXT) AS FILE_PATHFROM USED_GOODS_BOARD AS UGB JOIN USED_GOODS_FILE AS UGF ON UGB.BOARD_ID = UGF.BOARD_IDWHERE UGB.VIEWS = (SELECT MAX(VIEWS) FROM USED_GOODS_BOARD)ORDER BY UGF.FILE_ID DESC; 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/les..