SQL Interview Questions

SQL Interview Questions


In this article, I will share my SQL interview experience with questions and Answers.

1. How to find the Nth highest salary from a table
 
Finding the Nth highest salary in a table is the most common question asked in interviews.
Here is the list of ways to do this....

To find the highest salary it is straight forward. We can simply use the Max() function as shown below.

Select Max(Salary) from Employees

To get the second highest salary use a sub query along with Max() function as shown below.

Select Max(Salary) from Employees where Salary < (Select Max(Salary) from Employees)

A. To find nth highest salary using Sub-Query

SELECT TOP 1 SALARY
FROM (
      SELECT DISTINCT TOP N SALARY
      FROM EMPLOYEES
      ORDER BY SALARY DESC
      ) RESULT
ORDER BY SALARY

B. To find nth highest salary using CTE

WITH RESULT AS
(
    SELECT SALARY,
           DENSE_RANK() OVER (ORDER BY SALARY DESC) AS DENSERANK
    FROM EMPLOYEES
)
SELECT TOP 1 SALARY
FROM RESULT
WHERE DENSERANK = N

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