（105）Examine the structure of the PROMOS table:

name Null Type

PROMO_ID NOT NULL NUMBER(3)

PROMO_NAME VARCHAR2(30)

PROMO_START_DATE NOT NULL DATE

PROMO_END_DATE NOT NULL DATE

You want to display the list of promo names with the message 'Same Day' for promos that started and ended on the same day.

Which query gives the correct output?

A. SELECT promo_name, NVL(NULLIF(promo_start_date, promo_end_date), 'Same Day') FROM promos;

B. SELECT promo_name, NVL(TRUNC(promo_end_date - promo_start_date), 'Same Day') FROM promos;

C. SELECT promo_name, NVL2(TO_CHAR(TRUNC(promo_end_date-promo_start_date)), NULL,'Same Day') FROM promos;

D. SELECT promo_name, DECODE((NULLIF(promo_start_date, promo_end_date)), NULL,'Same day') FROM promos;

答案：（D）

A（X），执行出现错误，因为NVL要求两个参的类型相同或兼容

B（X），同A

C（X），结果不正确，TRUNC函数的第2个参数被省略，则默认为'DD'

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OCP 1Z0-051-105