Problem

Write a SQL query to find the second highest salary from the employees table.
Example input:
+----+--------+
| Id | Salary |
+----+--------+
| 1  | 100    |
| 2  | 200    |
| 3  | 300    |
+----+--------+
Example output:
+--------+
| Salary |
+--------+
| 200    |
+--------+

Solution

SELECT MAX(Salary) AS Salary
FROM Employee
WHERE Salary < (SELECT MAX(Salary) FROM Employee)

/*

The solution above is optimal because it uses a subquery to find the maximum salary and then uses that value to find the second highest salary.

*/