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Data · Completely Free

Making the world of
data accessible.
At eye level.

SQL · Python · Pandas · Power BI — a single platform that brings together courses, interactive simulators, thousands of exercises, and real interview simulations from the world of analysts.

My goal is simple — To make the world of data accessible to as many people as possible, no expensive courses, no clunky translations, and no language barrier.

Start learning now ← Recommended learning track ←

370+

SQL challenges

11

Study chapters

24K

Rows in the simulator

100%

free

a bit about me

ABOUT · A bit about me

Hi, I'm Eliran Grossman, a data analyst and analytics team lead at Partner Communications. For years I’ve seen how hard it is for people here to break into the data field — most materials are in English, courses are expensive, and the jump to job interviews is confusing.

My goal is simple — to make the world of data accessible to as many people as possible, for free.

This site is exactly that: one place that brings together everything you need to learn SQL, Python, and Pandas from the basics to interview level, with real-world examples in language everyone understands.

Contact on LinkedIn WhatsApp

New on the site · The largest repository

Advanced SQL challenges — from intermediate to expert

The largest repository of real-world SQL challenges — 370 complex questions with 8 tables each, filtering by tags, personal solve tracking, and a randomize option. Everything you need for an interview or real practice.

Open the challenges ←

Multiple-Choice Questions · Choose a Level

QUIZ · 4 LEVELS

SELECT · WHERE · JOIN

Aggregation · Strings

Subqueries · Window

Choosing a query

Simulators and tools

INTERACTIVE

Write and run queries in the browser, 24K rows of real data

Power BI Simulator

DAX practice, building dashboards and interactive measures

SQL · 135 questions

Comprehensive practice

135 interactive SQL questions of all levels, organized by topic

PYTHON · 400 exercises

400 Python exercises

Two tracks on one page: 200 basic exercises for absolute beginners, and 200 advanced exercises up to dynamic programming and graphs. A full solution and explanation for every exercise

SQL · 200 exercises

200 SQL exercises for beginners

Just the basics: SELECT, WHERE, ORDER BY, GROUP BY and JOIN. A real database running in the browser, all tables visible in front of you, and a full solution for every exercise

PYTHON · 170 exercises

Python Simulator with Scoring

Guided practice by topic, with theory, scoring, and automatic checking

SQL Simulator — NBA Data

Practice queries on a real basketball games database

SQL · CHAMPIONS

SQL Simulator — Champions League

Queries on game, team and player data from the Champions League

SQL · NORTHWIND

SQL Simulator — Northwind

The classic database for learning SQL, with live practice in the browser

Search for an exercise by topic

Find exercises from across the site by the topic you want to practice

Python Playground

A Colab-like workspace with ready-made templates and a function library

All the Python and Pandas exercises

PYTHON & PANDAS · 1,790 exercises

PYTHON · 400 exercises

400 Python exercises · beginner and advanced

A track that starts from zero - variables, strings, lists, conditionals, loops, and dictionaries - and continues into an advanced track up to dynamic programming and graphs. 17 topics, a full solution and explanation for every exercise

PYTHON · 170 exercises

Python basics course

11 modules and 34 topics, from print to a capstone project. Theory and practice alongside the code

PYTHON · 330 exercises

Python Playground

Two tracks: 165 Python exercises and 165 Pandas exercises, LeetCode-style

PYTHON · 170 exercises

Simulator with scoring

Guided practice by topic, with scoring, theory and automatic checking

PYTHON · 100 exercises

100 Python exercises

Code exercises from easy to hard, each with automatic checking and an explanation

PANDAS · 150 exercises

10 modules: from your first DataFrame to GroupBy, merge, and Case Study analyses

PANDAS · 190 exercises

Pandas lessons — live code

The core of the course, including 20 advanced exercises with real matplotlib, NumPy, and scikit-learn

PANDAS · 100 exercises

100 Pandas exercises

Graduated code exercises, with automatic checking for each one

100 multiple-choice questions

Pandas quiz with a full explanation for every answer, across four levels

100 Pandas commands

The command guide every analyst needs, organized into 14 categories

Full courses

COURSES · FREE

SQL · 11 chapters

Full SQL course

From SELECT to Window Functions, with live practice and examples in the browser

PYTHON · 11 modules

170 code exercises that run in the browser with Pyodide, two learning tracks

PANDAS · 10 modules

DataFrame, groupby, merge, data cleaning with 150 exercises

100 Pandas commands

The complete guide to Pandas commands every analyst must know

POWER BI · 4 lessons

Full Power BI Course

167 topics: modeling, Power Query, M and DAX, with a reference of 122 functions

POWER BI · QUIZ

Power BI Quiz · 693 Questions

Multiple-choice questions: every choice immediately marks correct in green and incorrect in red, with a detailed explanation

Preparation for job interviews

INTERVIEW PREP

Recommended learning track

The optimal learning order for analysts starting out

Telecom interview

A job-interview simulation on Customer Churn with real telecom data

Insurance interview

An interview simulation on management fees with real insurance data

Daily challenge

A new SQL question every day to stay sharp and keep practicing

Additional resources

RESOURCES

SQL function library

All of SQL's functions in one place with usage examples

100 Python exercises

Live code in the simulator, sorted by difficulty level, a solution for every exercise

Guided practice

Organized exercises with explanation and step-by-step

MySQL tutorials

Videos filmed on MySQL

SQL Server tutorials

Video tutorials on SQL Server

100 multiple-choice questions in Pandas

A 100-question quiz with a full explanation for every answer

PANDAS · 100 exercises

100 Pandas exercises

Graduated code exercises from easy to hard, with automatic checking

POWER BI · Lesson 1

Power BI — basics

Introduction to Power BI: loading data, your first visualization, and building a report

POWER BI · Lesson 2

Power BI — Modeling

Star schema, relationships between tables, and correct model architecture

POWER BI · Lesson 3

Power BI — Power Query

Cleaning data, reshaping it, and automating the loading process

POWER BI · Lesson 4

Power BI — M and DAX

The M language for data processing and DAX for calculating measures

DAX function guide

122 DAX functions, with an explanation and example for each

POWER BI · Updates

Power BI updates

What's new in every monthly Microsoft release, explained simply

Guided projects

Full end-to-end data projects, step by step

SQL study material

Organized summaries, examples, and explanations for every topic

SQL lessons guide

The course's video lessons, arranged in learning order

SQL questions for a job interview

A quiz focused on questions that recur in data-role interviews

Installation guide

How to install MySQL and SQL Server on your computer