SQL Lessons

Learn the basics of querying data with SELECT statements. Understand how to retrieve specific columns from a table.

Master the WHERE clause to filter rows based on conditions. Learn about comparison operators and logical conditions.

Use ORDER BY to sort your results and LIMIT to control how many rows are returned.

Learn how to combine data from multiple tables using INNER JOIN. See how tables relate to each other.

Understand the difference between INNER and LEFT JOINs. Learn when to use LEFT JOIN and see null-extended rows.

Use COUNT, SUM, AVG, MIN, and MAX to perform calculations on your data.

Learn to group rows and perform aggregate calculations on each group.

Master complex JOINs with junction tables. Learn to query many-to-many relationships.