Post #2397

🧠Top 10 Real-World SQL Scenarios with Sample Answers📊💻 1. Find Duplicate Records in a Table SELECT email, COUNT(*) FROM customers GROUP BY email HAVING COUNT(*) > 1; 2. Find the Second Highest Salary SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees); 3. Customers with More Than 3 Orders in Last 30 Days SELECT customer_id FROM orders WHERE order_date >= CURRENT_DATE - INTERVAL '30 days' GROUP BY customer_id HAVING COUNT(*) > 3; 4. Calculate Monthly Revenue SELECT DATE_TRUNC('month', sale_date) AS month, SUM(amount) AS monthly_revenue FROM sales GROUP BY month ORDER BY month; 5. Find Employees Without Managers SELECT * FROM employees WHERE manager_id IS NULL; 6. Join Two Tables and Filter by Amount SELECT o.order_id, c.name, o.amount FROM orders o JOIN customers c ON o.customer_id = c.customer_id WHERE o.amount > 100; 7. Use CASE for Conditional Logic SELECT name, CASE WHEN score >= 90 THEN 'Excellent' WHEN score >= 75 THEN 'Good' ELSE 'Needs Improvement' END AS rating FROM students; 8. Find Top-Selling Products SELECT product_id, SUM(quantity) AS total_sold FROM sales GROUP BY product_id ORDER BY total_sold DESC LIMIT 5; 9. Identify Inactive Users SELECT user_id FROM users WHERE last_login < CURRENT_DATE - INTERVAL '90 days'; 🔟 Calculate Conversion Rate SELECT COUNT(*) FILTER (WHERE status = 'converted') * 100.0 / COUNT(*) AS conversion_rate FROM leads; 💡Pro Tip: Practice these with real datasets and explain your logic clearly in interviews. 💬Tap ❤️ if this helped you prep smarter!