QUESTION NO: 30
View the Exhibit and examine the description for the CUSTOMERS table.
You want to update the CUST_CREDIT_LIMIT column to NULL for all the customers, where
CUST_INCOME_LEVEL has NULL in the CUSTOMERS table. Which SQL statement will
accomplish the task?
A.UPDATE customers SET cust_credit_limit = NULL WHERE CUST_INCOME_LEVEL = NULL;
B.UPDATE customers SET cust_credit_limit = NULL WHERE cust_income_level IS NULL;
C.UPDATE customers SET cust_credit_limit = TO_NUMBER(NULL) WHERE cust_income_level = TO_NUMBER(NULL);
D.UPDATE customers SET cust_credit_limit = TO_NUMBER(' ',9999) WHERE cust_income_level IS NULL;
Answer: B
答案解析:
参考:163:http://blog.youkuaiyun.com/rlhua/article/details/12886715
Explanation:
本文介绍了一种使用SQL更新特定条件下的记录的方法。具体来说,当CUST_INCOME_LEVEL为NULL时,如何将CUST_CREDIT_LIMIT设置为NULL。通过正确使用IS NULL条件,可以有效地更新表中的记录。
6305

被折叠的 条评论
为什么被折叠?



