INNER JOIN logic

Learn that INNER JOIN returns only matching rows.

INNER JOIN combines two tables through a shared column. Only rows matching in both tables appear.

SELECT * FROM orders
INNER JOIN customers
  ON orders.customer_id = customers.id;

This query matches orders with customers.

All columns are selected from orders. customers ON is joined, keeping only matching rows.

INNER JOIN logic — details

INNER JOIN is the most common join. Unmatched rows are ignored.

For example, a customer with no orders or an order whose customer was deleted does not appear; only records with a match in both tables are listed.

Join orders with customers using INNER JOIN.

Show example solution

SELECT *
FROM orders
INNER JOIN customers
  ON orders.customer_id = customers.id;

Add the join

SELECT * FROM orders
____ customers ON orders.customer_id = customers.id;

Show answer

SELECT * FROM orders
INNER JOIN customers ON orders.customer_id = customers.id;