Core · Databases Free to read

SQL and Databases tutorial

Ask a real database questions, join tables, change data safely and design tables that stay correct.

6 lessonsabout 8 h

Learn it by doing

The interactive course has the same lessons with an editor next to them: run every example, answer the quizzes and solve exercises that are checked the moment you submit. Free to start, no sign-up.

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Ask questions

Filter, sort and limit the rows of one table.

1 SELECT and WHEREHow do you ask a database a question?2 Sorting and limitingHow do you sort, limit and tidy a result?

Summaries and joins

Count by group and combine tables.

3 Grouping and countingHow do you summarise many rows into a few numbers?4 Joining tablesHow do you combine two tables?

Change and design

Write data safely and design good tables.

5 Changing data and transactionsHow do you change data safely?6 Keys, constraints and indexesHow do you design tables that stay correct?