문제코드WITH RECURSIVE ANCESTOR AS ( SELECT ID, PARENT_ID, 1 AS GENERATION FROM ECOLI_DATA WHERE PARENT_ID IS NULL UNION SELECT C.ID, C.PARENT_ID, (A.GENERATION + 1) AS GENERATION FROM ECOLI_DATA C, ANCESTOR A WHERE C.PARENT_ID = A.ID)SELECT COUNT(*) AS COUNT, GENERATIONFROM ANCESTORWHERE ID NOT IN (SELECT PARENT_ID FROM ANCESTOR WHERE PARENT_ID IS NOT NULL)GROUP BY GENERATIONOR..

문제코드SELECT YEAR(O.SALES_DATE) AS YEAR, MONTH(O.SALES_DATE) AS MONTH, COUNT(DISTINCT O.USER_ID) AS PURCHASED_USERS, ROUND((COUNT(DISTINCT O.USER_ID)/ (SELECT COUNT(*) FROM USER_INFO WHERE YEAR(JOINED) = 2021)),1) AS PURCHASED_RATIOFROM ONLINE_SALE OWHERE O.USER_ID IN (SELECT USER_ID FROM USER_INFO WHERE YEAR(JOINED) = 2021)GROUP BY YEAR, MONTHORDER BY YEAR, MONTH; 출처: 프로그래머스 코딩 테스..

문제코드WITH CODE_SUM AS ( SELECT (SELECT SUM(CODE) FROM SKILLCODES WHERE CATEGORY = 'Front End') AS FRONT_END, (SELECT SUM(CODE) FROM SKILLCODES WHERE NAME = 'Python') AS PYTHON, (SELECT SUM(CODE) FROM SKILLCODES WHERE NAME = 'C#') AS CSHARP),CTE AS ( SELECT CASE WHEN SKILL_CODE & c.FRONT_END > 0 AND SKILL_CODE & c.PYTHON > 0 THEN 'A' WHEN SKI..

문제코드WITH CAR AS (SELECT CAR_ID FROM CAR_RENTAL_COMPANY_RENTAL_HISTORY GROUP BY CAR_ID HAVING MAX(END_DATE) 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/lessons/157339

문제코드SELECT ID, EMAIL, FIRST_NAME, LAST_NAMEFROM DEVELOPERSWHERE SKILL_CODE & ( SELECT SUM(CODE) FROM SKILLCODES WHERE CATEGORY = 'Front End' ) > 0ORDER BY ID ASC; 출처: 프로그래머스 코딩 테스트 연습, https://school.programmers.co.kr/learn/courses/30/lessons/276035