How do you return orders with customer details using an inner join between orders and customers on customer_id?

• A. SELECT * FROM orders o INNER JOIN customers c ON o.customer_id = c.id;
• B. SELECT * FROM orders o LEFT JOIN customers c ON o.customer_id = c.id;
• C. SELECT * FROM orders o RIGHT JOIN customers c ON o.customer_id = c.id;
• D. SELECT * FROM orders o JOIN customers c ON o.order_id = c.id;

Answer: (D)

When you want orders along with the details of the customers who placed them, you connect the two tables using the foreign key that links them. Orders has a customer_id field that points to Customers.id, so you join on that key. An inner join returns only rows where there is a matching customer for an order, which is what you typically want for a combined view of orders and their customer data.

A correct example looks like:

SELECT o., c. FROM orders o INNER JOIN customers c ON o.customer_id = c.id;

If you used a left join, you’d include orders that have no matching customer; a right join would bring in customers without corresponding orders. Joining on a different column, like o.order_id, would mismatch the intended relationship between orders and customers.