text: /*
  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 query should return 200 as the second highest salary. If there is no second highest salary, then the query should return null.
  
  +---------------------+
  | SecondHighestSalary |
  +---------------------+
  | 200                 |
  +---------------------+*/
  
  
  
  select max(Salary) as SecondHighestSalary from Employee where Salary < (select Max(Salary) from Employee)