UPDATE invoices
    SET
    payment_total = invoice_total 0.5
    payment_date = due_date
    WHERE client_id =
    (SELECT client_id
    FROM clients
    WHERE name = ‘Myworks’*)

    从客户表内选择在CA和NY地区的客户
    UPDATE invoices
    SET
    payment_total = invoice_total 0.5
    payment_date = due_date
    WHERE client_id *IN
    (SELECT client_id
    FROM clients
    WHERE state in (‘CA’, ‘NY’))

    从消费者表内选择积分超过3000分的客户ID，并将order表内的备注
    更改为金牌用户
    UPDATE orders
    SET
    comments = “GOLD CUSTOMER”
    WHERE customer_id IN
    (SELECT customer_id
    FROM customers
    WHERE points > 3000)