## Solution

#### Approach: Using sub-query and LIMIT clause [Accepted]

Algorithm

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.

MySQL

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


#### Approach: Using IFNULL and LIMIT clause [Accepted]

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

MySQL

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