Where to learn data analysis in 2026: choose by the skill you need

-- the query is correct
AUTUMN20 orders   €91.81 average
without the code  €36.60 average

You can write a query and still hesitate when someone asks, “Did the promotion work?” You can also understand the business question and need help translating it into SQL. Those are different starting points, and they need different practice.

Choose a learning resource by the work you want to get better at: reading and writing SQL, following a broad curriculum, preparing for interviews, or defining and checking an analysis. You may want more than one.

Disclosure: we build Atterna, one of the options below. This is a guide to choosing practice, not an independent ranking. Course contents, access and prices change; check the linked providers before enrolling.

Quick picks

• Free SQL basics: SQLBolt.
• Broad curriculum with a certificate: Google Data Analytics.
• SQL interview drills: DataLemur.
• Defining and checking an analysis: Atterna Cases; the first case is free.

Options to compare

These categories overlap. A course platform may also offer projects or teach AI verification: for example, DataCamp has an AI for Data Analysts course. Do not assume a topic is absent because a site is in a different row of the table.

If you are starting from zero

Start with a short SQL lesson and check whether you enjoy working with tables. Learn to select columns, filter rows, count and group results. A small table is useful when you are learning a new operation; a larger business dataset gives you more decisions to make about what it means.

Atterna Start offers ten sessions on one fictional marketplace: from watching a purchase become rows to JOINs and window functions. Days 1–2 are free without an account; a free account opens all ten. See the session-by-session plan.

If you prefer a broad course, inspect its syllabus and one sample assignment before committing. Look for feedback on your reasoning as well as whether your code runs. A certificate can document completion, but it does not by itself establish job readiness.

If you know SQL but freeze at an unclear request

Practise what happens before and after the query. What decision does the number support? Which definition fits? What comparison would be misleading? What can you responsibly recommend?

In Atterna’s Bigger baskets?, marketing wants to write “the code grows baskets 2.5×” into the December plan. The number is real. The claim isn’t. You choose clarifying questions, define the basket metric, query the data and check whether the comparison supports that claim.

Try Bigger baskets? — free, no account, basic SQL. Find out why a real 2.5× is the wrong number to plan on. If you do not write SQL yet, Wrong Number covers the first skill through three requests: deciding who belongs in a count.

Atterna’s focus is learning to understand and question data. The simulator supplies the setting for practice; the reasoning also applies to an AI answer, a spreadsheet or a dashboard. Meridian extends the work into a longer analyst scenario with eight episodes, as part of Atterna Analyst (€59, one-time payment). Atterna is a small, early product and does not issue a certificate.

If you want to use AI without accepting every answer

Look for exercises where you must inspect evidence, not just improve the wording of a prompt. Can you identify an unstated denominator? Check whether a join duplicates money? Distinguish a descriptive difference from a causal effect?

Try the seven-question checklist on an answer you already have. Then use the metric definition template to rewrite its brief. A convincing explanation from an assistant is still something to verify against the data and calculation.

A practical way to choose

1. Pick one task you currently cannot do confidently.
2. Complete one sample lesson or case that exercises it.
3. Check the feedback: does it explain why your answer is wrong, or only reveal the expected answer?
4. Try a changed example without the walkthrough. Can you explain what changed and why?
5. Only then decide whether the full course fits your time and budget.

For a suggested starting point within Atterna, the level check has six questions and needs no account. It is a routing aid, not a professional certification.

FAQ

What is the best website to learn data analysis?

There is no single best option for every starting point. SQLBolt offers introductory SQL practice; DataLemur focuses on interview preparation; broad platforms and certificates cover more tools. Atterna focuses on defining, checking and interpreting numbers through business scenarios. Try a sample that matches the skill you need.

Can I learn data analysis for free?

You can begin with free SQL tutorials and public datasets. Atterna’s Wrong Number, level check, first Case, guides and first two Start days are free without an account; a free account opens all ten Start days. Advanced access and feedback vary across providers; check current terms rather than assuming every course or project is free.

How is Atterna different from an SQL exercise site?

Atterna asks you to practise the work around the query: clarify a request, define a metric, check the comparison and explain a decision. Start also teaches SQL itself. Other platforms may cover overlapping skills; the useful comparison is what you actually do in an exercise and the feedback you receive.

Should I learn SQL if AI can write queries?

Reading SQL helps you check which rows an assistant counted and whether joins or filters changed the result. You do not need to memorise every function, but you need enough understanding to test its work. See learning data analysis with AI.