（100）View the Exhibit and examine the structure of the PROMOTIONS table. Which SQL statements are valid? (Choose all that apply.)

A.

SELECT promo_id, DECODE(NVL(promo_cost,0), promo_cost,

promo_cost * 0.25, 100) "Discount"

FROM promotions;

B.

SELECT promo_id, DECODE(promo_cost, 10000,

DECODE(promo_category, 'G1', promo_cost *.25, NULL), NULL) "Catcost"

FROM promotions;

C.

SELECT promo_id, DECODE(NULLIF(promo_cost, 10000),

NULL, promo_cost*.25, 'N/A') "Catcost"

FROM promotions;

D.

SELECT promo_id, DECODE(promo_cost, >10000, 'High', <10000, 'Low')

"Range" FROM promotions;

答案：（A、B）

解析：

C（X），decode会将所有的结果值转换成第一个结果值的类型，因此’N/A’转数字会失败。

D（X），decode中每个比较的对象应该为一个表达式。（>10000，不为表达式）

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OCP 1Z0-051-100