SQL Practice Questions for Beginners and Experts

Introduction

Ever found yourself stuck staring at a SQL problem, wondering how to approach it? Whether you’re just starting out or you’ve been in the data trenches for years, working through SQL practice questions can sharpen your querying skills and boost your confidence.

In this guide, we’ll cover the best types of SQL problems for all skill levels, walk through practical examples, and share unique insights and resources that go beyond typical tutorials.

Why SQL Practice Matters in 2025

SQL remains the backbone of data analysis, database management, and backend development. In fact, according to Stack Overflow’s 2024 Developer Survey, SQL is still among the top 5 most used programming languages globally.

Practicing SQL is not just about syntax. It’s about learning how to think in queries—how to interpret business problems as SQL problems.

Whether you’re preparing for a job interview, managing databases, or analyzing customer data, practicing SQL is key to staying sharp.

Getting Started: SQL Practice Questions for Beginners

If you’re new to SQL, start with foundational questions that reinforce SELECT, WHERE, and JOIN statements.

1. Basic SELECT Queries

Retrieve all columns from the employees table.
Show the first name and last name of employees earning more than $50,000.

2. Filtering Data

Select all customers from the customers table who are based in the USA.
Find all products priced between $100 and $500.

3. Sorting and Limiting

List the top 10 highest-paid employees.
Show products ordered by their creation date in descending order.

4. Simple JOINs

Retrieve all orders along with customer names using INNER JOIN.
Find all products that have never been sold using LEFT JOIN.

Pro Tip: Use platforms like SQLZoo or Mode Analytics SQL Tutorial to get real-time feedback while practicing.

SQL-Practice-Questions-for-Beginners-and-Experts-Interview

Intermediate to Advanced SQL Practice Questions

Once you’re comfortable with the basics, you’ll need to tackle real-world scenarios with complex logic.

5. Aggregation and Grouping

Calculate the total sales for each product category.
Count how many users signed up each month in the past year.

6. Subqueries

List employees who earn more than the average salary.
Show all customers who made more purchases than the average customer.

7. Window Functions

Assign a rank to each employee based on salary within their department.
Calculate a running total of sales by month.

8. Case Statements

Create a column that labels customers as ‘High’, ‘Medium’, or ‘Low’ based on purchase volume.

9. Data Cleaning & Formatting

Remove duplicate entries from a dataset.
Format date fields into YYYY-MM-DD.

Expert-Level SQL Challenges

If you’re preparing for technical interviews or data analyst roles, these questions test not just your SQL knowledge but your problem-solving ability.

10. Recursive Queries (CTEs)

Find all employees under a specific manager in a hierarchical org chart.
Generate a calendar table for the current year.

11. Complex Joins & Union

Combine customer data from multiple regions, resolving conflicts.
Identify gaps in sequences, such as missing invoice numbers.

12. Optimization

Improve a slow-running query fetching millions of rows.
Analyze and reduce query execution time using EXPLAIN plans.

Learn more about query optimization from PostgreSQL’s official documentation.

How to Create Your Own SQL Practice Questions

Sometimes the best way to learn is to reverse-engineer your own problems. Here’s how:

Think of a Business Problem: For example, “How many customers made repeat purchases last month?”
Design a Table Structure: Include fields like customer_id, purchase_date, amount.
Write and Solve Queries: Test different ways to derive insights.

This approach simulates the data scenarios you’ll face in real jobs, helping you build transferable skills.

Visual Summary: Common SQL Functions by Skill Level

Skill Level	SQL Topics
Beginner	SELECT, WHERE, ORDER BY, LIMIT
Intermediate	GROUP BY, JOINs, Subqueries, CASE
Expert	CTEs, Window Functions, Optimization

Common Mistakes to Avoid When Practicing SQL

Overlooking NULL values: Always consider how NULLs affect aggregations and comparisons.
Forgetting table aliases: They make your queries readable and prevent errors in JOINs.
Ignoring indexing and performance: Especially important in large datasets.

Real-World Application of SQL Practice Questions

During a freelance project for a retail client, I was tasked with generating weekly sales reports. What seemed like a simple GROUP BY query quickly turned complex with irregular time gaps, promotional overrides, and duplicate orders.

Practicing advanced SQL saved the day. By applying WINDOW FUNCTIONS and COMMON TABLE EXPRESSIONS (CTEs), I could clean and segment the data efficiently, saving hours of manual work.

This firsthand experience reinforced one thing: theory means little without practice.

Final Thoughts

SQL is more than a database language—it’s a critical thinking tool for anyone working with data. The more SQL practice questions you solve, the more intuitive your problem-solving becomes.

Start simple, build up gradually, and challenge yourself with real-world scenarios. Before you know it, you’ll not only be writing better queries but also thinking more like a data professional.

What’s Next?

Ready to test your skills? Try creating your own dataset or solve new problems on the platforms mentioned above. Don’t forget to share your favorite SQL challenge or ask your questions in the comments below.

💬 Let us know: What SQL topic do you find the most challenging?