interval

示例:

select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') currenttime,

       to_char(sysdate - interval '7' year,'yyyy-mm-dd hh24:mi:ss') intervalyear,   

       to_char(sysdate - interval '7' month,'yyyy-mm-dd hh24:mi:ss') intervalMonth,   

       to_char(sysdate - interval '7' day,'yyyy-mm-dd hh24:mi:ss') intervalday,   

       to_char(sysdate - interval '7' hour,'yyyy-mm-dd hh24:mi:ss') intervalHour,   

       to_char(sysdate - interval '7' minute,'yyyy-mm-dd hh24:mi:ss') intervalMinute,   

       to_char(sysdate - interval '7' second,'yyyy-mm-dd hh24:mi:ss') intervalSecond  

  from dual;

add_months

示例:

select add_months(sysdate,1) newtime from dual;

months_between

示例:

 select months_between(to_date('03-31-2015','MM-DD-YYYY'),to_date('12-31-2014','MM-DD-YYYY')) "MONTHS" FROM DUAL;

next_day

示例:

select sysdate today, next_day(sysdate,6) the_week from dual;

to_date

示例:

select to_date('2009-07-04 05:02:01','yyyy-mm-dd hh24:mi:ss') the_time from dual;

to_char

示例:

select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') the_time,

       to_char(sysdate,'yyyy') the_year,

       to_char(sysdate,'mm') the_month,

       to_char(sysdate,'dd') the_day,

       to_char(sysdate,'day') the_week,

       to_char(sysdate,'hh24')the_hour,

       to_char(sysdate,'mi') the_minute,

       to_char(sysdate,'ss') the_second

from dual;