If you’re preparing for a data analyst role, mastering SQL is essential.

Most interviews include practical SQL questions to test your ability to analyze data, not just write syntax.

In this guide, you’ll learn common SQL queries asked in data analyst interviews with clear examples and explanations.

Sample Dataset

Assume a table called orders:

order_id	customer_id	region	revenue	order_date
1	101	West	500	2026-01-01
2	102	East	700	2026-01-02
3	101	West	300	2026-01-03

1. Total Revenue

Question:

Calculate total revenue.

SELECT SUM(revenue) AS total_revenue
FROM orders;

2. Revenue by Region

Question:

Find total revenue per region.

SELECT region, SUM(revenue) AS total_revenue
FROM orders
GROUP BY region;

3. Count Orders per Customer

Question:

How many orders does each customer have?

SELECT customer_id, COUNT(*) AS total_orders
FROM orders
GROUP BY customer_id;

4. Top Customers by Revenue

Question:

Find top customers based on revenue.

SELECT customer_id, SUM(revenue) AS total_revenue
FROM orders
GROUP BY customer_id
ORDER BY total_revenue DESC;

5. Filter Recent Orders

Question:

Get orders after a specific date.

SELECT *
FROM orders
WHERE order_date >= '2026-01-01';

6. Average Revenue

Question:

Find average order revenue.

SELECT AVG(revenue) AS avg_revenue
FROM orders;

7. Using CASE WHEN

Question:

Categorize orders based on revenue.

SELECT order_id,
       CASE
           WHEN revenue > 500 THEN 'High'
           ELSE 'Low'
       END AS revenue_category
FROM orders;

8. Find Duplicate Customers

Question:

Find customers with more than one order.

SELECT customer_id, COUNT(*) AS order_count
FROM orders
GROUP BY customer_id
HAVING COUNT(*) > 1;

9. Get Top N Records

Question:

Find top 2 highest revenue orders.

SELECT *
FROM orders
ORDER BY revenue DESC
LIMIT 2;

10. Running Total (Window Function)

Question:

Calculate cumulative revenue.

SELECT order_date,
       SUM(revenue) OVER (ORDER BY order_date) AS running_total
FROM orders;

11. Rank Customers

Question:

Rank customers by total revenue.

SELECT customer_id,
       SUM(revenue) AS total_revenue,
       RANK() OVER (ORDER BY SUM(revenue) DESC) AS rank
FROM orders
GROUP BY customer_id;

12. Join Example

Assume another table customers:

| customer_id | name |

Question:

Join orders with customer names.

SELECT o.order_id, c.name, o.revenue
FROM orders o
JOIN customers c
ON o.customer_id = c.customer_id;

What Interviewers Are Testing

These queries test your ability to:

• Aggregate data
• Filter and group results
• Use joins
• Apply business logic
• Work with real-world scenarios

It’s not just about syntax, it’s about solving problems.

How to Prepare for SQL Interviews

• Practice real-world datasets
• Understand concepts like GROUP BY, JOIN, and window functions
• Explain your logic clearly
• Optimize your queries

Interviewers value clarity and reasoning.

Common Mistakes to Avoid

• Forgetting GROUP BY when using aggregation
• Using HAVING instead of WHERE incorrectly
• Not handling NULL values
• Writing inefficient queries

Avoiding these mistakes can set you apart.

SQL is one of the most important skills for data analysts, and interviews are designed to test how well you can use it to solve real problems.

By practicing these common queries, you’ll build confidence and improve your ability to handle real interview questions.

Consistency and practice are key to mastering SQL.

FAQs