Customers With Payments, Each Listed Once

Question

Which of these queries list every customer who has at least one payment exactly once, without DISTINCT? Choose all that apply.

Answer 1

SELECT c.customer_id, c.last_name FROM customer AS c LEFT JOIN payment AS p ON p.customer_id = c.customer_id WHERE p.payment_id IS NOT NULL;

Answer 2

SELECT c.customer_id, c.last_name FROM customer AS c CROSS JOIN payment AS p WHERE p.customer_id = c.customer_id;

Answer 3

SELECT c.customer_id, c.last_name FROM customer AS c WHERE c.customer_id IN (SELECT p.customer_id FROM payment AS p);

Answer 4

SELECT c.customer_id, c.last_name FROM customer AS c JOIN payment AS p ON p.customer_id = c.customer_id;

Answer 5

SELECT c.customer_id, c.last_name FROM customer AS c WHERE EXISTS (SELECT 1 FROM payment AS p WHERE p.customer_id = c.customer_id);

Answer 6

SELECT c.customer_id, c.last_name FROM customer AS c JOIN payment AS p ON p.customer_id = c.customer_id GROUP BY c.customer_id, c.last_name;