Find max og second max løn for en medarbejder tabel MySQL

Du kan bare køre 2 forespørgsler som indre forespørgsler for at returnere to kolonner:

select
  (SELECT MAX(Salary) FROM Employee) maxsalary,
  (SELECT MAX(Salary) FROM Employee
  WHERE Salary NOT IN (SELECT MAX(Salary) FROM Employee )) as [2nd_max_salary]

SQL Fiddle Demo