SELECT H1.name, H1.grade, H2.name, H2.grade
FROM Likes l1, Highschooler h1, Highschooler H2
WHERE EXISTS (
  SELECT ID1, ID2
  FROM Likes l2, Highschooler h3, Highschooler h4
  WHERE l2.ID1=l1.ID2 AND l2.ID2=l1.ID1 AND h3.ID=l2.ID1
        AND h4.Id=l2.ID2 AND h3.name>h4.name
)
AND h1.ID=l1.ID1 AND h2.ID=l1.ID2
ORDER BY H1.name