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SQL & data analysis portfolio

Your SQL portfolio, built while you learn.

Every case and episode you finish becomes a GitHub-ready project: the question, your SQL, result tables, charts and your decision.

7 sample projects · fictional learner and marketplace data

Try case 1 free About 17 minutes · no accountSee the sample repository ↓
projects / meridian-1-record-week / README.md
  • SQL
  • DuckDB
  • Meridian episode 1

Record week

The dashboard shows record sales. What really happened to the money?

queries.sql · query 5 of 6, last step
SELECT k.week_start,
       k.commission_net_eur - k.platform_discount_eur
         - k.card_fees_eur - m.marketing_eur AS contribution_eur
FROM weekly AS k
JOIN marketing AS m ON m.week_id = k.week_id
ORDER BY k.week_start;
My call

Stop the promo and run a test on new customers.

6 SQL queries · checked on 2 datasets · memo in my own wordsOpen this project in the sample ↓

Your course work, as a GitHub repository.

This is the sample: the real files of 7 projects. Open a project to read its README — the question, why it isn’t obvious, the SQL, result tables, charts and the decision.

atterna-com/data-analyst-portfolio-examplePublic7 projects · 36 SQL queries
README.md

Sample learner — SQL & data analysis portfolio

Sample portfolio. Atterna generated this repository from a synthetic learner profile (“Sample learner”, not a real person) on Atterna’s fictional marketplace data. Your own export looks like this, built from your own queries and words.

Work samples from Atterna, a simulator where you learn data analysis by doing a junior analyst’s job. Each project below is work I actually did there: the business question, my SQL, the result and the call I made.

7 projects · 36 SQL queries

The data is fictional. Meridian is a synthetic online marketplace built for training: no real customers, sellers or company. The tasks and data are Atterna’s; the SQL and the decisions are mine.

Projects

ProjectBusiness questionWhat I didHeadlineMy call
1. Take rate fell by more than a point in the promo week.Case study · 3 SQL queries · decision memo from my choicesTake rate from the case data: 12.6% in W37, 11.5% in the promo week.No reversal: the mix explains the drop
2. Vera wants to drop the most-refunded products from the December promo.Case study · 4 SQL queries · decision memo from my choicesRefunds booked: €16,073 on 323 refunds.No defensible cut yet: the ranking moves and item-level evidence is thin
3. The dashboard shows record GMV. What really happened to the money?Meridian episode 1 · 6 SQL queries · memo in my own words−€9,984.50 Platform contribution in the promo weekStop the promo and run a test
4. Product's report says conversion went up.Meridian episode 2 · 5 SQL queries · recommendationOn the fair part the badge probably raises conversion: +1.5 pp, 95% interval +0.2 pp to +2.9 pp.Turn the badge on now for web and app 5.1 and 5.3
5. The retention dashboard shows a collapse.Meridian episode 3 · 5 SQL queries · recommendation7.20% Month-1 retention of promotion customersA discount only on a new customer's first order of €40 or more
6. In January the platform launches the Trusted Shop programme.Meridian episode 4 · 5 SQL queries · recommendationThe problem sits with a few shops: 17 shops break the rules, 9 also beyond chance; together they carry 11% of GMV and up to 40%…Judge shops with 30+ orders on cancellations (≤5%) and late shipments (≤15%)
7. Friday. I need a final report for the board: for each category — orders, GMV, average order value and share of total GMV.Course final project · 8 SQL queriesAll 8 queries passed the checkSUM() OVER (), ROW_NUMBER and PARTITION BY, Running total

About this work

  • Every SQL answer passed Atterna’s automatic checker, which compares the result with a hidden reference on two versions of the data, so a hard-coded number fails. It is Atterna’s own check, not a third-party certification.
  • These are my saved SQL submissions. Queries supplied by the task and recognised starter templates are labelled. The automatic checks assess the results, not independent authorship.
  • Words are labelled. “My own words” is text I typed. “Assembled from my choices” is built from options I selected in the exercise, so it is not free text.

For hiring managers

  • Per query: each project’s “How it was checked” lists attempts and hint use. Queries the task supplied or pre-filled, and answers identical to the finished query in the hints, are not counted as first tries. Hint use that was not recorded is reported as not recorded, not as zero.
  • Not shown: who typed the work. Practice is not proctored, and every Atterna learner gets the same tasks on the same fictional data. Ask me to walk you through any query.

How to read this repository

  • Each folder in projects/ is one project. Start with its README.md: the question, my approach, the result and the decision.
  • queries.sql holds all the SQL of a project in one file. results/ has the result of each query as CSV, plus a chart where the result is one label and one number.

Next step

Next: I repeat this method on a public dataset. Edit this line and link the repository when it is ready.

Sample generated by Atterna from synthetic progress on fictional Meridian data. Task and data: Atterna. SQL and decisions: the sample learner’s. 10 October 2026. Data version: 2026-09-26.en1.

For hiring managers

  • What a record shows. Saved SQL, each answer checked against a hidden reference on two versions of the data, so a typed-in number fails. Attempts and hint use are listed per query; typed words are labelled apart from selected options.
  • Not counted as first tries. Queries the task supplied or pre-filled, and answers identical to the finished query in the hints. Where hint use was not recorded, the record says “not recorded”, never zero.
  • What it cannot show. Who did the work. Practice is not proctored, and every learner gets the same tasks on the same fictional marketplace. Ask the candidate to walk you through one query.
Download the example ↓View on GitHub ↗

The downloadable example is in English. Your own export uses your chosen course language.

Free account

Build a portfolio like this from your own work

A free account packs your finished work as GitHub-ready projects.

  • All 10 days of the SQL courseFrom your first table to JOINs and window functions
  • Meridian episode 1A full analyst week: the record that wasn’t
  • Your first portfolio projectFinished work as a ready GitHub project, with your SQL and charts
  • Progress on any deviceYour cheat sheet and review cards go with you
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Your course work becomes your portfolio.

  1. Finish a case or project

    Practise, use hints when needed, and make your recommendation.

  2. Review what you are sharing

    Open Portfolio in your account. Choose completed projects and check your queries, results and explanations.

  3. Download and make it yours

    Export the ZIP. Read the README, add your context and explain any supplied code. Publish it on GitHub yourself when you are ready.

The export includes the projects you have completed. Atterna does not publish your work automatically.

Already learning? Open your portfolio →

Build your first analysis before you pay.

Case 1 is free. Start from its ready query, check the comparison and choose a recommendation supported by your numbers.

Try case 1 free →Never written SQL? Start day 1 free →

Continue with the level that fits you

Atterna Foundations€19
  • Case rounds: Cases 2–3
  • Trap drills
  • Practice, 41 SQL tasks
  • Sandbox
What’s inside →Atterna Analyst€59
  • Meridian episodes 1–8
  • Everything in Foundations
What’s inside →

One-time · early-access price. The sample is free to inspect and download.

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