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Raahaao Code: SQL

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

9+ ore di lezioni · 2 progetti · €35

Ti aiuta a prepararti per: IT Specialist – Databases (Certiport) · Oracle Database SQL, 1Z0-071 (Oracle)

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Cosa imparerai, piano per piano

  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

I due progetti sul tetto

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.

Domande

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