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Answer: Either LEFT OUTER JOIN or RIGHT OUTER JOIN can be used
The correct answer is to use either a `LEFT OUTER JOIN` or a `RIGHT OUTER JOIN`. This is because the requirement is to fetch all records from the `customers` table (including those without orders) and only matching records from the `orders` table. A `LEFT OUTER JOIN` with `customers` on the left and `orders` on the right, or a `RIGHT OUTER JOIN` with `orders` on the left and `customers` on the right, will both satisfy the requirement. This approach ensures that all customers are included in the results, regardless of whether they have placed any orders.
Author: LeetQuiz Editorial Team
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A data engineer needs to join two tables, customers and orders, on the condition c.customer_id = o.order_customer_id. The goal is to retrieve details of all customers, including those who have not placed any orders, along with the details of orders they have placed. Given the schemas of both tables, which join operation should be used to achieve this?
A
RIGHT OUTER JOIN
B
INNER JOIN
C
FULL OUTER JOIN
D
LEFT OUTER JOIN
E
Either LEFT OUTER JOIN or RIGHT OUTER JOIN can be used
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