👉 “Top 5 SQL Query Patterns Every Developer Should Know for Interviews”

Intro:
SQL is a core interview topic for developers, data engineers, and backend engineers.
Instead of memorizing random queries, focus on 5 query patterns that interviewers love to ask again and again.

🔹 1. Find the Second Highest Salary
SELECT MAX(salary)
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);

Tests: Nested queries, MAX, comparison logic.

🔹 2. Count Employees in Each Department
SELECT department, COUNT(*)
FROM employees
GROUP BY department;

Tests: GROUP BY, aggregation.

🔹 3. Find Duplicate Records
SELECT email, COUNT()
FROM users
GROUP BY email
HAVING COUNT() > 1;

Tests: HAVING vs WHERE, aggregation filter.

🔹 4. Get Employees Who Don’t Have a Manager
SELECT name
FROM employees
WHERE manager_id IS NULL;

Tests: NULL handling.

🔹 5. Find Top N Records (e.g., Top 3 Salaries)
SELECT DISTINCT salary
FROM employees
ORDER BY salary DESC
LIMIT 3;

Tests: LIMIT, ORDER BY, DISTINCT.

🔥 Interview Tip

Don’t just write queries — always explain your thought process.
Interviewers want clarity, not just code.

✅ Conclusion

These 5 SQL query patterns cover 80% of the real interview questions you’ll face.
If you master them, you’ll walk into SQL rounds with confidence.

👉 Call to Action:
For step-by-step SQL interview prep, diagrams, and tricky questions, check out:
FullStackPrep.dev – SQL Interview Prep Guide

Tags:

sql #database #interviewprep #backend #programming