# Question

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                 |
+---------------------+


# Solution 1

select max(Salary) as SecondHighestSalary from Employee where Salary != (select max(Salary) from Employee);


# Solution 2

Sort the distinct salary in descend order and then utilize the LIMIT clause to get the second highest salary.

SELECT DISTINCT
Salary AS SecondHighestSalary
FROM
Employee
ORDER BY Salary DESC
LIMIT 1 OFFSET 1


However, this solution will be judged as ‘Wrong Answer’ if there is no such second highest salary since there might be only one record in this table. To overcome this issue, we can take this as a temp table.

SELECT
(SELECT DISTINCT
Salary
FROM
Employee
ORDER BY Salary DESC
LIMIT 1 OFFSET 1) AS SecondHighestSalary
;


Another way to solve the ‘NULL’ problem is to use IFNULL funtion as below.

SELECT
IFNULL(
(SELECT DISTINCT Salary
FROM Employee
ORDER BY Salary DESC
LIMIT 1 OFFSET 1),
NULL) AS SecondHighestSalary;