Inner Join Basics — Solution & ExplanationProblems / Inner Join Basics / EditorialApproach

INNER JOIN orders with customers on customer_id. This keeps only orders that have a matching customer.

Select the required columns from both tables.

Order by order_id.

Key InsightAn INNER JOIN is the default join type. It filters out rows from both sides that don't have a match. Here, customers 4 (Diana), 6 (Frank), and 8 (Hank) have no orders, so they don't appear.Hints

An INNER JOIN returns only rows that have matching values in both tables.

Use table aliases (o, c) to keep the query readable.

Customers without orders will not appear in the result — that's the expected behavior.

Solve Inner Join Basics yourself →