ocp 11g考試題庫詳解：1Z0-051-110題，完整題庫請點(diǎn)擊這里聯(lián)系老師咨詢了解

110. View the Exhibit and examine the structure of the CUSTOMERS table.

Using the CUSTOMERS table, you need to generate a report that shows the average credit limit for

customers in WASHINGTON and NEW YORK.

Which SQL statement would produce the required result?

A. SELECT cust_city, AVG(cust_credit_limit)

FROM customers

WHERE cust_city IN ('WASHINGTON','NEW YORK')

GROUP BY cust_credit_limit, cust_city;

B. SELECT cust_city, AVG(cust_credit_limit)

FROM customers

WHERE cust_city IN ('WASHINGTON','NEW YORK')

GROUP BY cust_city,cust_credit_limit;

C. SELECT cust_city, AVG(cust_credit_limit)

FROM customers

WHERE cust_city IN ('WASHINGTON','NEW YORK')

GROUP BY cust_city; 按照城市來取平均值

D. SELECT cust_city, AVG(NVL(cust_credit_limit,0))

FROM customers

WHERE cust_city IN ('WASHINGTON','NEW YORK');

Answer: C

試題解析：

A答案：此處是按照cust_credit_limit, cust_city;這兩個一起分組的。

B答案，與A答案一樣，按照cust_credit_limit, cust_city;這兩個一起分組的。

C答案，按照cust_city來分組，與題意復(fù)合

D答案：缺少group by