Second Highest Salary

• Problem
  Write a SQL query to get the second highest salary from the Employee table.
  +----+--------+
  | Id | Salary |
  +----+--------+
  | 1 | 100 |
  | 2 | 200 |
  | 3 | 300 |
  +----+--------+
  For example, given the above Employee table, the second highest salary is 200. If there is no second highest salary, then the query should return null.

• Code
  select max(Salary) from Employee where Salary < (select max(Salary) from Employee);