选择所有 country 字段值为以下列表中的值的客户
('Norway', 'Sweden', 'Denmark')
SELECT * FROM customers WHERE country @(34);
SELECT * FROM customers WHERE country IN ('Norway', 'Sweden', 'Denmark');
SELECT * FROM customers WHERE country IN ('Norway','Sweden','Denmark');
SELECT * FROM customers WHERE country IN ('Norway', 'Sweden','Denmark');
SELECT * FROM customers WHERE country IN ('Norway','Sweden', 'Denmark');