Welcome

Welcome to the learnsqlonline.org free interactive SQL tutorial.

SQL (pronouned either as S-Q-L or Sequel) is a powerful language for querying and analyzing any amount of data in the world. It is the most important tool for developers, analysts and data scientists alike for being able to deal with data.

SQL is commonly used for Business Intelligence so companies can make operative decisions on how to act based on data generated by the business. It is also used for researching data to create new insights by aggregating vast amounts of data. In the new big-data era, it is now possible to query petabytes of data using a single query using novel data warehouse technologies (for example: Hadoop, Spark, BigQuery, Presto/Amazon Athena, and more).

SQL can also be used to construct long-running data pipelines and process data for business purposes - Spark is a great example of a technology that utilizes SQL syntax to create data pipelines that can continuously process large amounts of data and turn it into another form of useful data, either for insights or for generating new data out of existing data.

To learn SQL on this website there is no need to download anything - Just click on the chapter you wish to begin from, and follow the instructions. Good luck!

learnsqlonline.org is still under construction - If you wish to contribute tutorials, please click on Contributing Tutorials down below.

Learn the Basics

• Hello, World!
• Selecting data
• Creating tables
• Inserting rows
• Updating rows
• Deleting rows
• Joining tables
• Group by
• Aggregate functions
• The HAVING statement
• Distinct queries
• Order by

Advanced tutorials

• String operations
• Inner and outer joins
• The UNION statement
• The CASE statement
• Combining INSERT INTO and SELECT
• Subqueries
• Indexing
• Altering tables
• Views
• Window functions

Contributing Tutorials

Read more here: Contributing Tutorials