Lv2. 레드 와인 도수와 퀄리티https://solvesql.com/problems/alcohol-degree-and-quality/SELECT * FROM winesWHERE quality >= 8 AND alcohol  Lv2. 보상 고객 목록입니다https://solvesql.com/problems/compensated-customers/SELECT order_date, order_id, customer_nameFROM ordersWHERE order_date BETWEEN '2018-04-01' AND '2018-04-05'ORDER BY order_date ASC, order_id ASC Lv2. 팁 많이 준 고객들의 특징https://solvesql.com/problems/high-tipp..

Lv1. 많이 주문한 테이블 찾기https://solvesql.com/problems/find-tables-with-high-bill/SELECT * FROM tipsWHERE total_bill > (SELECT AVG(total_bill) FROM tips)

Lv1. 최근 올림픽이 개최된 도시https://solvesql.com/problems/olympic-cities/SELECT year, UPPER(SUBSTR(CITY,1,3)) AS cityFROM gamesWHERE year >= 2000ORDER BY year DESC❗SUBSTR() 사용해서 특정 칼럼의 첫글자부터 세번째 글자까지 추출 : SUBSTR(칼럼,시작위치,끝위치)❗UPPER() 사용해서 대문자로 변환 Lv1. Catherine 감독의 영화https://solvesql.com/problems/catherine-movie/SELECT title, directors, age, genresFROM moviesWHERE directors LIKE 'Catherine%' Lv1. 제목이 모음으로..

Lv1. 데이터 그룹으로 묶기https://solvesql.com/problems/group-by/SELECT quartet , ROUND(AVG(x),2) AS x_mean , ROUND(VAR_SAMP(x),2) as x_var , ROUND(AVG(y),2) as y_mean , ROUND(VAR_SAMP(y),2) as y_varFROM pointsGROUP BY quartet❗표본 분산을 구하는 문제이므로 VAR_SAMP()를 사용 Lv1. 그룹 별 중복값이 있는지 확인하기https://solvesql.com/problems/duplicate-in-group/SELECT quartet , x , COUNT(*) AS cntFROM pointsGROUP BY quartet, xH..

Lv1. 모든 데이터 조회하기https://solvesql.com/problems/select-all/SELECT *FROM points Lv1. 일부 데이터 조회하기https://solvesql.com/problems/select-where/SELECT *FROM pointsWHERE quartet = 'I' Lv1. 데이터 정렬하기https://solvesql.com/problems/order-by/SELECT *FROM pointsWHERE quartet = 'I'ORDER BY y ASC Lv1. 우리 레스토랑에 온 부자 손님https://solvesql.com/problems/rich-customer/SELECT day, time, sizeFROM tipsORDER BY total_bill DE..

Lv4. 그룹별 조건에 맞는 식당 목록 출력하기https://school.programmers.co.kr/learn/courses/30/lessons/131124WITH T1 AS ( SELECT * FROM REST_REVIEW AS RR WHERE RR.MEMBER_ID = (SELECT MEMBER_ID FROM REST_REVIEW GROUP BY MEMBER_ID ORDER BY COUNT(*) DESC LIMIT 1))SELECT MP.MEMBER_NAME, T1.REVIEW_TEXT , DATE_FORMAT(..

Lv4. 보호소에서 중성화한 동물https://school.programmers.co.kr/learn/courses/30/lessons/59045SELECT AI.ANIMAL_ID, AI.ANIMAL_TYPE, AI.NAMEFROM ANIMAL_INS AS AI LEFT JOIN ANIMAL_OUTS AS AO ON AI.ANIMAL_ID = AO.ANIMAL_ID WHERE AI.SEX_UPON_INTAKE LIKE '%INTACT%' AND AO.SEX_UPON_OUTCOME NOT LIKE '%INTACT%'❗LEFT JOIN 으로 테이블 결합❗테이블 결합 시 WHERE 사용해서 조건 걸기 Lv4. 식품분류별 가장 비싼 식품의 정보 조회하기https://school.progr..

Lv3. 부서별 평균 연봉 조회하기https://school.programmers.co.kr/learn/courses/30/lessons/284529SELECT HD.DEPT_ID, HD.DEPT_NAME_EN , ROUND(AVG(HE.SAL),0) AS AVG_SALFROM HR_DEPARTMENT AS HD JOIN HR_EMPLOYEES AS HE ON HD.DEPT_ID = HE.DEPT_IDGROUP BY DEPT_ID, DEPT_NAME_ENORDER BY AVG(HE.SAL) DESC❗ROUND(), AVG() 사용해서 포맷 맞추기❗JOIN 사용해서 테이블결합❗ORDER BY 절에 AVG() 조건 달기 Lv3. 대장균의 크기에 따라 분류하기 1https://school.progr..