[HR] Placements*

• Advanced Join > multiple joins on the same table and compare
  https://www.hackerrank.com/challenges/placements/problem?isFullScreen=true

select t1.name
from (
    select s.id
          ,s.name
          ,p.salary
    from students s
    inner join packages p
    on s.id = p.id
) t1
inner join (
    select f.id
          ,f.friend_id
          ,p.salary
    from friends f
    inner join packages p
    on f.friend_id = p.id
) t2
on t1.id = t2.id
where t1.salary < t2.salary
order by t2.salary asc