데이터 공부를 기록하는 공간

https://www.hackerrank.com/challenges/interviews/problem Interviews | HackerRank find total number of view, total number of unique views, total number of submissions and total number of accepted submissions. www.hackerrank.com SELECT CON.contest_id, CON.hacker_id, CON.name, SUM(total_submissions) as A, SUM(total_accepted_submissions) as B, SUM(total_views) as C, SUM(total_unique_views) as D FROM..

https://www.hackerrank.com/domains/sql?filters%5Bskills%5D%5B%5D=SQL%20%28Advanced%29 Solve SQL Code Challenges A special-purpose language designed for managing data held in a relational database. www.hackerrank.com ☆ Draw The Triangle 1 SET @num = 21; SELECT REPEAT("* ", @num:=@num-1) /* for without table */ FROM INFORMATION_SCHEMA.TABLES WHERE @num > 0 Draw The Triangle 2 SET @num = 0; SELECT ..

https://www.hackerrank.com/domains/sql?filters%5Bskills%5D%5B%5D=SQL%20%28Intermediate%29 Solve SQL Code Challenges A special-purpose language designed for managing data held in a relational database. www.hackerrank.com Contest Leaderboard SELECT hacker_id, name, sum(score) FROM (select S.challenge_id challenge_id, H.hacker_id hacker_id, H.name name, max(S.score) score from Hackers H LEFT JOIN S..

↑https://www.hackerrank.com/domains/sql?filters%5Bskills%5D%5B%5D=SQL%20%28Intermediate%29 Solve SQL Code Challenges A special-purpose language designed for managing data held in a relational database. www.hackerrank.com ☆The Report select if(g.Grade >=8, s.Name, NULL), g.Grade, s.Marks from Students s left join Grades g on s.Marks between g.Min_Mark and g.Max_Mark order by g.Grade desc, s.Name ..