oracle查询时间语句有哪些？

select to_char(sysdate,’yyyy-mm-dd hh24:mi:ss’) as nowTime from dual;

select to_char(sysdate,’yyyy’) as nowYear from dual;

select to_char(sysdate,’mm’) as nowMonth from dual;

select to_char(sysdate,’dd’) as nowDay from dual;

select to_char(sysdate,’hh24′) as nowHour from dual;

select to_char(sysdate,’mi’) as nowMinute from dual;

select to_char(sysdate,’ss’) as nowSecond from dual;