OCP-1Z0-051-V9.02-81题

81. You are currently located in Singapore and have connected to a remote database in Chicago.

You issue the following command:

SQL> SELECT ROUND(SYSDATE-promo_begin_date,0)     

FROM promotions     

WHERE (SYSDATE-promo_begin_date)/365 > 2;

PROMOTIONS is the public synonym for the public database link for the PROMOTIONS table.

What is the outcome?

A. a n error because the ROUND function specified is invalid

B. a n error because the WHERE condition specified is invalid

C. number of days since the promo started based on the current Chicago date and time

D. number of days since the promo started based on the current  Singapore date and time

Answer: C

 答案解析：

参考：http://blog.csdn.net/rlhua/article/details/12848395

日期-日期，返回的是天数，是一个数字，

由本地连接到远程，SYSDATE是一个 SQL 函数，它用于返回当前所连接的远程服务器上数据库的日期和时间。

故选C.