OCP 19c ÈÏÖ¤¿¼ÊÔ1Z0-082¿¼ÊÔÌâ¿â£¨µÚ4Ì⣩-CUUGÄÚ²¿Ñ§Ô±°æ082Ìâ¿â½âÎö

4.Which two statements are true about date/time functions in a session where NLS_DATE_FORMAT is set to DD-MON-YYYY HH24:MI:SS? (Choose two.)

A. CURRENT_TIMESTAMP returns the same date and time as SYSDATE with additional details of fractional seconds

B. SYSDATE can be queried only from the DUAL table

C. CURRENT_DATE returns the current date and time as per the session time zone

D. SYSDATE can be used in expressions only if the default date format is DD-MON-RR

E. SYSDATE and CURRENT_DATE return the current date and time set for the operating system of the database server

F. CURRENT_TIMESTAMP returns the same date as CURRENT_DATE

Answer: CE

(½âÎö£ºdual Ö»ÊÇÒ»¸öΪÁËÓï·¨ÍêÕûÉè¼ÆµÄÐéÄâµÄ±í£¬ÕâЩº¯Êý¶¼¿ÉÒÔ»ùÓÚijÕűí½øÐÐÖ´ÐС£CURRENT_TIMESTAMP ·µ»ØµÄÐÅÏ¢ÊÇ×î¶àµÄ£¬°üº¬Ê±ÇøÐÅÏ¢¡£)

SQL> select CURRENT_TIMESTAMP from dual;

CURRENT_TIMESTAMP

---------------------------------------------------------------------------

14-JUL-20 02.52.00.783461 PM +08:00

SQL> select sysdate from dual;

SYSDATE

--------------------

14-JUL-2020 15:23:32

SQL> select sysdate from emp;

SYSDATE

--------------------

14-JUL-2020 15:24:31