목록STUDY/SQL_HACKERRANK (11)

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[MySQL] 기본문법 코딩테스트

LIKE - where절과 함께 특정 패턴을 검색할 때 사용 SELECT * FROM EMPLOYEE WHERE EMPLOYYE LIKE 'a%'; LIKE 'a%' // a로 시작 되는 모든 것 LIKE 'a_%_%' // a로 시작되고 최소 3이상의 길이를 가진 것 LIKE '_a%' // 두번째 자리에 a가 들어가는 모든 것 IN - where절 내 여러값을 설정하고 할 때 사용 - 연산 속도가 빠름 - or 연산과 유사 SELECT * FROM EMPLOYEE WHERE COUNTRY in ('UK', 'KOREA') // country가 UK나 KOREA 인 경우 BETWEEN - WHERE절 내 검색 조건으로 범위 지정하고자 할때 사용 - between A and B, A이상 B이하 SELEC..
STUDY/SQL_HACKERRANK 2021. 10. 20. 18:01
[HackerRank][SQL][Advanced Join] Interviews ☆☆

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..
STUDY/SQL_HACKERRANK 2021. 10. 19. 20:36
[hackerrank][SQL][Advanced]

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 ..
STUDY/SQL_HACKERRANK 2021. 10. 19. 19:29
[hackerrank][SQL][Intermediate]#3

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..
STUDY/SQL_HACKERRANK 2021. 10. 18. 23:49
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