52、(12-11) choose the best answer:

Examine the structure and data in the PRICE_LIST table:

You plan to give a discount of 25% on the product price and need to display the discount amount

in the same format as the PROD_PRICE.

Which SQL statement would give the required result?

A) SELECT TO_CHAR (TO_NUMBER (prod_price)*.25, '$99,999.00')

FROM PRICE_LIST;

B) SELECT TO_CHAR(prod_price*.25, '$99,999.99')

FROM PRICE_LIST;

C) SELECT TO_CHAR(TO_NUMBER(prod_price,'$99,999.99')*.25,'$99,999.00')

FROM PRICE LIST;

D) SELECT TO_NUMBER (TO_NUMBER(prod_price, '$99,999.99')*.25, '$99,999.00')

FROM PRICE_LIST;

Answer:A

(解析：其实 B 答案也可以实现要求，但是它不是最好的，这里需要 to_number 转换函数，因为 prod_price 本身是 varchar2 类型，可以用如下语句实验：

SELECT TO_CHAR(to_number(sal)*.25, '$99,999.99')

FROM emp;

)