EXTRACT() 函式

--EXTRACT() 函式用於提取日期/時間的單獨部分，比如年、月、日、小時、分鐘等等。 

select sysdate,

       extract(year from sysdate),

       extract(month from sysdate),

       extract(day from sysdate)

  from dual s;

  

  

SELECT EXTRACT(HOUR FROM TIMESTAMP '2010-01-10 11:12:13'),

       EXTRACT(minute FROM TIMESTAMP '2010-01-10 11:12:13'),

       EXTRACT(second FROM TIMESTAMP '2010-01-10 11:12:13')

  FROM DUAL;