SQL Programming Resources on Telegram: “SQL Interview Series

SQL Interview Series — Part 1

Hi guys, let's start a SQL interview series covering frequently asked and important SQL interview questions.

Each part will cover 1 practical interview question with:

✅ Problem statement

✅ SQL solution

✅ Approach

✅ Interview tip

📌 Question 1: Find the Second Highest Salary

Suppose you have an Employee table:

Employee

• employee_id

• employee_name

• salary

Example data:

employee_id| employee_name| salary

1| Amit| 50000

2| Rahul| 80000

3| Priya| 70000

4| Neha| 90000

5| Raj| 80000

❓ Find the second-highest salary from the Employee table.

💡 Approach

First, we need to identify the highest salary.

Then, we need the highest salary that is less than the maximum salary.

One simple approach is to use a subquery:

SELECT MAX(salary) AS second_highest_salary
FROM Employee
WHERE salary < (
    SELECT MAX(salary)
    FROM Employee
);

Output:

second_highest_salary

80000

🔎 Why does this work?

The inner query:

SELECT MAX(salary)
FROM Employee;

returns:

90000

Then the outer query considers only salaries below 90000:

50000

70000

80000

80000

Finally, MAX() returns:

80000

⚠️ Important Interview Point

If the question asks for the second-highest DISTINCT salary, this approach works because duplicate salaries are naturally treated as one value.

For example:

90000

80000

80000

70000

The second-highest distinct salary is still 80000.

💯 Double Tap ❤️ For Part-2