ลูกค้าชื่อ Carole และนามสกุล Bernhard กลายเป็นลูกค้าเมื่อใด?ไม่จำเป็นต้องใช้ทุกโต๊ะ
When did customer with first name as Carole and last name as Bernhard became a customer?It is not neccessary to use all the tables.
 Customers:  (date_became_customer [ VARCHAR ] first_name [ VARCHAR ] last_name [ VARCHAR) ]
SELECT date_became_customer FROM Customers WHERE first_name = "Carole" AND last_name = "Bernhard"