HackerRank SQL 문제 풀기 - Placements

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안녕하세요? 분석하는 디제이입니다.

 

오늘은 HackerRank 사이트에 있는 SQL문제를 풀어보려고 합니다.

 

난이도는 Intermediate구요, 제목은 Placements입니다.

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문제입니다.

You are given three tables: Students, Friends and Packages. Students contains two columns: ID and Name.

Friends contains two columns: ID and Friend_ID(ID of the ONLY best friend).

Packages contains two columns: ID and Salary(offered salary in thousands per month).

 

 

Write a query to output the names of those students whose best friends got offered a higher salary than then. 

Names must be ordered by the salary amount offered to the best friends. It is guaranteed that no two students got same salary offer. 

 

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정답입니다.

 

제가 작성한 정답입니다.

SELECT
A.NAME
FROM STUDENTS AS A
INNER JOIN FRIENDS AS B ON A.ID = B.ID 
LEFT JOIN PACKAGES AS C ON A.ID = C.ID 
LEFT JOIN PACKAGES AS D ON B.FRIEND_ID = D.ID
WHERE C.SALARY < D.SALARY
ORDER BY D.SALARY

 

 

궁금한 점 있으시면 댓글 달아주세요.

 

감사합니다.