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■ solvesql   □ 코딩테스트 : SQLite / 연습문제 / 난이도5https://solvesql.com/problems/?page=1 https://solvesql.com/problems/?page=1 solvesql.com   □ 연습문제1. 폐쇄할 따릉이 정류소 찾기 1COS() 함수 : 파라미터 n(라디안으로 표현되는 각도)의 코사인 값을 반환하는 함수sin() 함수 : 인수 n의 사인(sine)값을 반환하는 함수 acos() 함수 : n의 역사인(arc cosine) 값을 반환하는 함수(인수 n은 -1 ~ 1범위,  반환 값은 0 ~ pi(라디안)의 범위 값 반환)radians() 함수 : 도 단위 각도를 라디안 단위로 등가 변환하는 함수하버사인 공식(haversine fornula) ..

■ 출처- 코딩테스트 : SQLite / 연습문제 / 난이도4https://solvesql.com/problems/?page=1  https://solvesql.com/problems/?page=1 solvesql.com   ■ 연습문제 1. 가구 판매의 비중이 높았던 날 찾기SELECT order_date, COUNT(DISTINCT CASE WHEN category='Furniture' THEN order_id END) AS furniture, ROUND(COUNT(DISTINCT CASE WHEN category='Furniture' THEN order_id END)/(COUNT(DISTINCT order_id)+0.00)* 100, 2) AS furniture_pctFROM recor..

■ 출처- 코딩테스트 : SQLite / 연습문제 / 난이도3https://solvesql.com/problems/?page=1 https://solvesql.com/problems/?page=1 solvesql.com   ■ 연습문제 1. 복수 국적 메달 수상한 선수 찾기SELECT a.nameFROM records AS r JOIN athletes AS a ON r.athlete_id = a.id JOIN games AS g ON r.game_id = g.id JOIN teams AS t ON r.team_id = t.idWHERE r.medal IS NOT NULL AND g.year >= 2000GROUP BY r.athlete_idHAVING COUNT(DISTINCT t.tea..

■ 출처- 코딩테스트 : SQLite / 연습문제 / 난이도2https://solvesql.com/problems/?page=1 https://solvesql.com/problems/?page=1 solvesql.com   ■ 연습문제 1. 두 테이블 결합하기SELECT DISTINCT records.athlete_idFROM events RIGHT JOIN records ON events.id = records.event_idWHERE events.sport = 'Golf' 2. 레스토랑 웨이터의 팁 분석SELECT day, time , ROUND(AVG(tip), 2) AS avg_tip , ROUND(AVG(size),2) AS avg_size FROM tips GROUP BY ..

■ 출처- 코딩테스트 : SQLite / 연습문제 / 난이도1https://solvesql.com/problems/?page=1 https://solvesql.com/problems/?page=1 solvesql.com  ■ 연습문제1. 모든 데이터 조회하기SELECT * FROM points  2. 일부 데이터 조회하기SELECT *FROM pointsWHERE quartet = 'I'  3. 데이터 정렬하기SELECT *FROM pointsWHERE quartet = 'I'ORDER BY y ASC  4. 데이터 그룹으로 묶기SELECT quartet, ROUND(AVG(x), 2) AS x_mean, ROUND(VARIANCE(x),2) AS x_var, ROUND(AVG..