1.当前日期的年份第一天和最后一天 第一天 select trunc(sysdate,'y') FROM DUAL; select trunc(sysdate,'yy') FROM DUAL; select trunc(sysdate,'yyy') FROM DUAL; select trunc(sysdate,'yyyy') FROM DUAL; 最后一天 select last_day(add_months(trunc(SYSDATE,'y'),11)) from dual 2.当前日期的月份第一天和最后一天 select trunc(sysdate,'MM') from dual; select last_day(sysdate) from dual;