MySQL JOIN Types Visualized

What You Will Learn

• INNER JOIN keeps only matching rows.
• LEFT JOIN keeps all rows from the left table even without matches.
• Always verify join keys and cardinality before shipping queries.

Sample SQL

SELECT o.id, u.name, o.total_amount
FROM orders o
LEFT JOIN users u ON o.user_id = u.id
WHERE o.created_at >= DATE_SUB(CURDATE(), INTERVAL 30 DAY);

Next Step

Try rewriting this query in your own schema, then use our tools to format and refine it.