1、
select extract(year from sysdate) from dual; 当前年
select extract(month from sysdate) from dual; 本年到当月的月数
select extract(day from sysdate) from dual; 本月到当日的天数
2、
select to_char(sysdate, 'yyyy') from dual;
select to_char(sysdate, 'MM') from dual;
select to_char(sysdAte, 'dd') from dual;