Free SQL Scenario Based Interview Questions
Preparing for a SQL interview can be daunting, especially when it comes to scenario-based questions. These questions assess your ability to apply SQL knowledge to real-world problems and demonstrate your problem-solving skills. Here are some free SQL scenario-based interview questions to help you ace your next interview:
General SQL Scenarios
1. Finding the Top Performing Salesperson:
You have a table called "sales" with columns for "salesperson_id", "product_id", and "total_sales". How would you find the salesperson with the highest total sales?
2. Identifying Customers with Multiple Orders:
You have a table called "orders" with columns for "customer_id" and "order_date". How would you identify customers who have placed more than one order?
3. Calculating Average Order Value:
You have a table called "orders" with columns for "order_id" and "total_amount". How would you calculate the average order value?
4. Identifying Products with Low Sales:
You have a table called "sales" with columns for "product_id" and "quantity_sold". How would you identify products that have sold less than 10 units in the last month?
5. Finding Duplicate Records:
You have a table called "customers" with columns for "customer_id", "first_name", and "last_name". How would you identify and remove duplicate customer records?
Scenario-Based SQL Questions with Hints
1. Finding the Most Popular Item in Each Category:
You have two tables: "products" (product_id, category_id, name) and "sales" (sale_id, product_id, quantity_sold). How would you find the most popular item (highest quantity sold) within each category?
Hint: Use GROUP BY and MAX() functions.
2. Identifying Customers Who Made Purchases on Consecutive Days:
You have a table called "orders" with columns for "customer_id" and "order_date". How would you identify customers who made purchases on two consecutive days?
Hint: Use LAG() or LEAD() window functions.
3. Calculating the Number of Orders Placed by Customers in Each Month:
You have a table called "orders" with columns for "customer_id" and "order_date". How would you find the number of orders placed by each customer in each month?
Hint: Use DATE_TRUNC() function to extract the month from the order date and GROUP BY customer and month.
Tips for Answering SQL Scenario-Based Questions
- Understand the Requirements: Carefully read the question and identify the desired output.
- Break Down the Problem: Divide the problem into smaller, manageable steps.
- Use SQL Keywords: Utilize SQL keywords like SELECT, FROM, WHERE, GROUP BY, ORDER BY, etc.
- Consider Performance: Think about optimizing your query for efficiency.
- Test Your Solution: Run your query on a sample dataset to verify the results.
Conclusion
Scenario-based SQL interview questions are designed to evaluate your ability to apply SQL knowledge to real-world problems. By practicing with these free SQL scenario-based interview questions, you can develop your problem-solving skills and confidently tackle any SQL challenge that comes your way. Remember to understand the requirements, break down the problem, and test your solution to ensure success. Good luck with your SQL interview!
