A) UPDATE orders
SET order_date = ‘12-mar-2007‘
AND order_total = TO_NUMBER(NULL)
WHERE order_id = 2455;
B) UPDATE orders
SET order_date = ‘12-mar-2007‘,
order_total = NULL
WHERE order_id = 2455;
C) UPDATE orders
SET order_date = TO DATE(‘12-mar-2007‘,‘dd-mon-yyyy‘),
SET order_total = TO NUMBER(NULL)
WHERE order_id = 2455;
D) UPDATE orders
SET order_date = ‘12-mar-2007‘,
order_total IS NULL
WHERE order_id = 2455;
Answer：D
(解析：注意语法)
【OCP-12c】CUUG 071题库考试原题及答案解析（14）
原文：http://blog.51cto.com/13854012/2351313