text: /**
  
  https://www.hackerrank.com/challenges/placements/problem
  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 them. Names must be ordered by the salary amount offered to the best friends. It is guaranteed that no two students got same salary offer.
  
  Sample Input
  
  
  
  Sample Output
  
  Samantha
  Julia
  Scarlet
  
  Explanation
  
  See the following table:
  
  
  
  Now,
  
  Samantha's best friend got offered a higher salary than her at 11.55
  Julia's best friend got offered a higher salary than her at 12.12
  Scarlet's best friend got offered a higher salary than her at 15.2
  Ashley's best friend did NOT get offered a higher salary than her
  The name output, when ordered by the salary offered to their friends, will be:
  
  Samantha
  Julia
  Scarlet
   */
  
  SELECT s.name
  FROM Students s
    JOIN Friends f ON s.id = f.id
    JOIN Packages p ON f.friend_id = p.id
    JOIN Packages p2 ON s.id = p2.id
  WHERE p2.salary < p.salary
  ORDER BY p.salary;