SQL Holmes

How it works

1. 1Sign in with your Skillancy account and choose your investigator.
2. 2Each chapter gives you one goal. Write a SQL query on the case tables and press Submit.
3. 3Solve all 10 chapters to name the culprit behind the howling on the moor.

The ten chapters

• Clue 1

  SELECT + WHERE

• Clue 2

  ORDER BY + LIMIT

• Clue 3

  GROUP BY + COUNT

• Clue 4

  INNER JOIN

• Clue 5

  GROUP BY + HAVING

• Clue 6

  Multi-table JOIN

• Deduction 1

  Subqueries

• Deduction 2

  CASE WHEN

• Confrontation

  Window functions

• Unmasking

  CTE + JOIN + window

Questions

Is SQL Holmes free?

Yes. It is free to play with a Skillancy account.

Do I need to know SQL?

No. The first chapters teach SELECT and WHERE step by step, then the case gets harder.

Does my query run in the browser?

Yes. A real Postgres database runs in your browser; answers are checked on our server.

Is the story the original novel?

No. It uses public-domain character names with an original plot and an original culprit.