Databases & SQL
Query, design, and change relational databases — right in your browser, no setup.
sql 17 Lessons
Every lesson runs in your browser — write real code, press Run, and the tasks check themselves. Free, no account needed, with notes in English and Chinese.
Lessons in this course
- history A short history of SQL
- usage What SQL is used for
- resources Where to learn more
- setup Set up your computer
- 01 Databases and SELECT
- 02 Choosing columns
- 03 Filtering with WHERE
- 04 AND, OR, NOT
- 05 Sorting with ORDER BY
- 06 Counting and averaging
- 07 LIKE, IN and BETWEEN
- 08 Grouping with GROUP BY
- 09 Tables, keys and relationships
- 10 INNER JOIN
- 11 Joins with grouping
- 12 Creating tables
- 13 Changing the schema
- 14 Inserting rows
- 15 Updating rows
- 16 Deleting rows
- 17 Normalisation