✨나만의 개발일지✨

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..