Top 50 SQL Queries for Job Interviews (With Answers)

SQL (Structured Query Language) is one of the most essential skills for software developers, data analysts, data engineers, and database administrators. Almost every technical interview that involves data includes SQL interview questions to test a candidate’s ability to retrieve, manipulate, and analyze data efficiently.

This article covers the Top 50 SQL Queries for Job Interviews, explained in a beginner-friendly yet interview-ready manner. Each query includes real-world use cases, practical examples, and clear SQL syntax to help you confidently crack SQL interviews.

Why SQL Queries Are Important in Job Interviews

• SQL is used in almost every data-driven application
• Interviewers assess problem-solving and logical thinking
• Queries reflect real-world business scenarios
• SQL tests your understanding of data relationships

Basic SQL Queries (Beginner Level)

1. Select All Records from a Table

Use Case: Retrieve all employee details from a database.

📄

SELECT * FROM employees;

2. Select Specific Columns

📄

SELECT name, salary FROM employees;

This query fetches only the required columns, improving performance and readability.

3. Use WHERE Clause

📄

SELECT * FROM employees WHERE department = 'IT';

4. Use DISTINCT Keyword

📄

SELECT DISTINCT department FROM employees;

5. Use ORDER BY Clause

📄

SELECT * FROM employees ORDER BY salary DESC;

6. Limit Records

📄

SELECT * FROM employees LIMIT 5;

7. Use AND / OR Operators

📄

SELECT * FROM employees WHERE department = 'HR' AND salary > 40000;

8. BETWEEN Operator

📄

SELECT * FROM employees WHERE salary BETWEEN 30000 AND 60000;

9. IN Operator

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SELECT * FROM employees WHERE department IN ('IT', 'Finance');

10. LIKE Operator

📄

SELECT * FROM employees WHERE name LIKE 'A%';

Intermediate SQL Queries (Most Asked in Interviews)

11. COUNT Function

📄

SELECT COUNT(*) FROM employees;

12. SUM Function

📄

SELECT SUM(salary) FROM employees;

13. AVG Function

📄

SELECT AVG(salary) FROM employees;

14. MIN and MAX

📄

SELECT MIN(salary), MAX(salary) FROM employees;

15. GROUP BY Clause

📄

SELECT department, COUNT(*) 
FROM employees 
GROUP BY department;

16. HAVING Clause

📄

SELECT department, COUNT(*) 
FROM employees 
GROUP BY department 
HAVING COUNT(*) > 5;

17. INNER JOIN

📄

SELECT e.name, d.department_name
FROM employees e
INNER JOIN departments d
ON e.department_id = d.id;

18. LEFT JOIN

📄

SELECT e.name, d.department_name
FROM employees e
LEFT JOIN departments d
ON e.department_id = d.id;

19. RIGHT JOIN

📄

SELECT e.name, d.department_name
FROM employees e
RIGHT JOIN departments d
ON e.department_id = d.id;

20. SELF JOIN

📄

SELECT a.name AS Employee, b.name AS Manager
FROM employees a
JOIN employees b
ON a.manager_id = b.id;

Advanced SQL Queries (Experienced-Level Interviews)

21. Subquery in WHERE Clause

📄

SELECT * FROM employees
WHERE salary > (SELECT AVG(salary) FROM employees);

22. Correlated Subquery

📄

SELECT name FROM employees e
WHERE salary > (
  SELECT AVG(salary) FROM employees WHERE department = e.department
);

23. EXISTS Operator

📄

SELECT name FROM employees e
WHERE EXISTS (
  SELECT 1 FROM departments d WHERE d.id = e.department_id
);

24. CASE Statement

📄

SELECT name,
CASE 
  WHEN salary > 60000 THEN 'High'
  WHEN salary BETWEEN 40000 AND 60000 THEN 'Medium'
  ELSE 'Low'
END AS salary_level
FROM employees;

25. UNION

📄

SELECT name FROM employees_2023
UNION
SELECT name FROM employees_2024;

26. UNION ALL

📄

SELECT name FROM interns
UNION ALL
SELECT name FROM employees;

27. DELETE with Condition

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DELETE FROM employees WHERE salary < 20000;

28. UPDATE Query

📄

UPDATE employees SET salary = salary + 5000 WHERE department = 'IT';

29. TRUNCATE vs DELETE

TRUNCATE removes all records faster and cannot be rolled back, while DELETE supports conditions and rollback.

30. Index Creation

📄

CREATE INDEX idx_salary ON employees(salary);

Scenario-Based SQL Interview Queries

31. Second Highest Salary

📄

SELECT MAX(salary) FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);

32. Duplicate Records

📄

SELECT name, COUNT(*) 
FROM employees 
GROUP BY name 
HAVING COUNT(*) > 1;

33. Employees Without Department

📄

SELECT * FROM employees WHERE department_id IS NULL;

34. Top 5 Salaries

📄

SELECT * FROM employees ORDER BY salary DESC LIMIT 5;

35. Highest Salary per Department

📄

SELECT department, MAX(salary)
FROM employees
GROUP BY department;

Additional Must-Know SQL Queries

Query No	Concept
36	Find NULL values
37	Use COALESCE
38	Find odd/even rows
39	Pagination
40	CTE (WITH clause)
41	Window Functions
42	ROW_NUMBER()
43	RANK()
44	DENSE_RANK()
45	Find Nth highest salary
46	Data normalization
47	ACID properties
48	Transactions
49	Views
50	Stored Procedures

Mastering these Top 50 SQL Queries for Job Interviews will significantly improve your confidence and problem-solving skills. Focus on understanding the logic behind each query rather than memorizing syntax. Practice real-world scenarios, optimize your queries, and always think from a business perspective.

Frequently Asked Questions (FAQs)

1. Are SQL queries still important for interviews?

Yes, SQL remains one of the most tested skills across IT, data, and analytics roles.

2. How many SQL queries should I practice?

Practicing 40–60 well-structured queries is sufficient for most interviews.

3. Are joins important in SQL interviews?

Absolutely. Joins are among the most frequently asked SQL interview topics.

4. What SQL level is expected for freshers?

Basic to intermediate SQL including SELECT, WHERE, JOIN, GROUP BY, and subqueries.

5. How can I improve SQL problem-solving skills?

Practice daily, analyze real datasets, and solve SQL challenges on interview platforms.