OCP-1Z0-新051-61题版本-59

QUESTION NO: 59

Evaluate the following two queries:

Which statement is true regarding the above two queries?

A. Performance would improve in query 2 only if there are null values in the CUST_CREDIT_LIMIT column

B. Performance would degrade in query 2

C. There would be no change in performance

D. Performance would improve in query 2

Answer: C

答案解析：

参考：55：http://blog.csdn.net/rlhua/article/details/11837463

Explanation:

Note: The IN operator is internally evaluated by the Oracle server as a set of OR conditions, such

as a=value1 or a=value2 or a=value3. Therefore, using the IN operator has no performance

benefits and is used only for logical simplicity.