IT, one system at a time

Modern IT runs on hundreds of systems: databases, data platforms, programming languages, clouds, servers and the tools that keep them running. This site has a course for each one, sorted into categories, so you can find a system by what it does. Every course starts from the beginning and goes to expert level, and every example is run on a real system before it goes on a page, with its true result shown under it.

Start here

• Preparing for a data engineering interview? Read the SQL interview fast track first. It says which chapters to read, in which order, in two days.
• Coming back to SQL after a while? The one-page cheat sheet brings most of it back in ten minutes.
• New to all of it? Start at chapter 1 of the SQL course.

Categories

Databases

SQL, from beginner to expert. Later: PostgreSQL, MySQL, SQL Server, Oracle, MongoDB, Redis.

Data engineering

Databricks and the medallion model (being written). Later: Spark, Airflow, dbt, Kafka.

Interview prep

Codility SQL and Python practice (being written).

Coming later

Data warehouses and BI · Programming · Cloud · DevOps · Servers and operating systems · Enterprise applications · Identity and security · Monitoring and operations · AI and machine learning.

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