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https://school.programmers.co.kr/learn/courses/30/lessons/157341 프로그래머스 코드 중심의 개발자 채용. 스택 기반의 포지션 매칭. 프로그래머스의 개발자 맞춤형 프로필을 등록하고, 나와 기술 궁합이 잘 맞는 기업들을 매칭 받으세요. programmers.co.kr [문제] 다음은 어느 자동차 대여 회사에서 대여 중인 자동차들의 정보를 담은 CAR_RENTAL_COMPANY_CAR 테이블과 자동차 대여 기록 정보를 담은 CAR_RENTAL_COMPANY_RENTAL_HISTORY 테이블입니다. CAR_RENTAL_COMPANY_CAR 테이블은 아래와 같은 구조로 되어있으며, CAR_ID, CAR_TYPE, DAILY_FEE, OPTIONS 는 각각 자동차 ..

https://school.programmers.co.kr/learn/courses/30/lessons/157339 프로그래머스 코드 중심의 개발자 채용. 스택 기반의 포지션 매칭. 프로그래머스의 개발자 맞춤형 프로필을 등록하고, 나와 기술 궁합이 잘 맞는 기업들을 매칭 받으세요. programmers.co.kr [문제] 다음은 어느 자동차 대여 회사에서 대여 중인 자동차들의 정보를 담은 CAR_RENTAL_COMPANY_CAR 테이블과 자동차 대여 기록 정보를 담은 CAR_RENTAL_COMPANY_RENTAL_HISTORY 테이블과 자동차 종류 별 대여 기간 종류 별 할인 정책 정보를 담은 CAR_RENTAL_COMPANY_DISCOUNT_PLAN 테이블 입니다. CAR_RENTAL_COMPANY_C..

https://www.hackerrank.com/challenges/placements/problem?isFullScreen=true Placements | HackerRank Write a query to output the names of those students whose best friends got offered a higher salary than them. www.hackerrank.com [코드] select sub.name from (select s.id, s.name, f.friend_id, p.salary from students as s inner join friends as f on s.id = f.id inner join packages as p on s.id = p.id) a..

https://www.hackerrank.com/challenges/the-report/problem?isFullScreen=true The Report | HackerRank Write a query to generate a report containing three columns: Name, Grade and Mark. www.hackerrank.com [코드] select case when b.grade >= 8 then a.name else 'NULL' end , b.grade, a.marks from Students as a inner join Grades as b on (a.Marks>=b.Min_Mark and a.Marks

https://www.hackerrank.com/challenges/weather-observation-station-18/problem?isFullScreen=true Weather Observation Station 18 | HackerRank Query the Manhattan Distance between two points, round or truncate to 4 decimal digits. www.hackerrank.com [코드] select Round(abs(max(LAT_N)-min(LAT_N))+abs(max(LONG_W)-min(LONG_W)),4) from STATION; [고찰] 이번 문제는 절댓값을 구하기 위해서 abs() 함수를 써야하는 것만 알면 쉽게 해결 할 수 있었다.

https://www.hackerrank.com/challenges/contest-leaderboard/problem?isFullScreen=true Contest Leaderboard | HackerRank Generate the contest leaderboard. www.hackerrank.com [코드] select b.hacker_id, b.name, sum(score) from (select hacker_id, challenge_id, max(score) as score from Submissions group by hacker_id, challenge_id) as a inner join Hackers as b on a.hacker_id = b.hacker_id group by b.hacker..

https://solvesql.com/problems/mentor-mentee-list/ https://solvesql.com/problems/mentor-mentee-list/ solvesql.com [코드] select a.employee_id as mentee_id, a.name as mentee_name, b.employee_id as mentor_id, b.name as mentor_name from employees as a left outer join employees as b on a.employee_id != b.employee_id where a.join_date > '2021-09-31' and b.join_date < '2020-01-01' and a.department != b.d..

https://solvesql.com/problems/artists-without-artworks/ https://solvesql.com/problems/artists-without-artworks/ solvesql.com [코드] select a.artist_id, a.name from artists as a left outer join artworks_artists as b on a.artist_id = b.artist_id where b.artist_id is null and a.death_year is not null [고찰] 이번 문제는 artists 테이블에서 artowrks_artists의 테이블과 중복되는 부분을 제거하여 MoMA에 등록은 되어있는 작가지만 전시한 작품은 없는 컬럼을 뽑아내..

https://solvesql.com/problems/characteristics-of-orders/ https://solvesql.com/problems/characteristics-of-orders/ solvesql.com [코드] select region as 'Region', sum(case when category = 'Furniture' then order_id end) as 'Furniture', sum(case when category = 'Office Supplies' then order_id end) as 'Office Supplies', sum(case when category = 'Technology' then order_id end) as 'Technology' from (sele..

https://solvesql.com/problems/daily-arppu/ https://solvesql.com/problems/daily-arppu/ solvesql.com [코드] select date(a.order_purchase_timestamp) as dt, count(DISTINCT a.customer_id) as pu, round(sum(b.payment_value), 2) as revenue_daily, round( sum(b.payment_value) / count(distinct a.customer_id), 2 ) as arppu from olist_orders_dataset as a inner join olist_order_payments_dataset as b on a.order_..