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Raahaao Code: SQL

Every app stores data. Learn to question it, shape it and protect it.

9+ hours of lessons · 2 projects · €35

Helps you prepare for: IT Specialist – Databases (Certiport) · Oracle Database SQL, 1Z0-071 (Oracle)

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What you'll learn, floor by floor

  1. 1

    Questions (Beginner)

    • What a database is, and your first SELECT
    • Filtering and sorting
    • Aggregates and GROUP BY
  2. 2

    Tables (Intermediate)

    • Creating tables and types
    • Keys and constraints
    • INSERT, UPDATE and DELETE
  3. 3

    Combining (Intermediate)

    • Joins
    • Subqueries and CTEs
    • NULL and dates
  4. 4

    Solid data (Job-ready)

    • Transactions and upserts
    • Indexes and EXPLAIN QUERY PLAN
    • Schema design and normalisation
  5. 5

    Pro (Job-ready)

    • Window functions
    • Safe migrations
    • SQL from code and injection
    • Access rules and row-level security

The two rooftop projects

Music-streaming database

Build the analytics layer for a small music-streaming service. You get six tables (artists, albums, tracks, users and plays) and ten questions the product team keeps asking: what is popular, who is listening, and when.

  • Create view q1: the 5 most played tracks with play counts.
  • q2: plays per day.
  • q3: users who never played anything.
  • q4: each album's total length in minutes, rounded to 1 decimal.
  • q5: the top artist by plays.
  • q6: tracks never played.
  • q7: each user's favourite artist (ties broken by artist name).
  • q8: average plays per user.
  • q9: the busiest hour of the day.
  • q10: tracks longer than their album's average length.

Data detective

Something is wrong in the shop's stock room. The inventory log says units went missing as "damaged", but the numbers do not add up.

  • View q1: stock now per product.
  • q2: products where the log disagrees with sales.
  • q3: write-offs by staff.
  • q4: write-offs by weekday.
  • q5: matching dates.
  • q6: a ROW_NUMBER ranking.
  • q7: a CTE combining it all.
  • r8 View culprit returns the single staff name.

Questions

Do I need to install anything?

No. Everything runs in your browser. For the projects you can also work on your own computer and upload your files.

Can I skip what I already know?

Yes. Once you own a tower, each floor has a skip test: score 8 out of 10 and that floor opens.

What is the refund policy?

Refunds within 5 days of purchase. After 5 days, no refunds or returns.

Do I keep access?

Yes. A tower you buy is yours, with no subscription.

Refund policy

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