--1.使用interval select trunc(sysdate) + (interval '1' second) * 1 from dual; select trunc(sysdate) + (interval '1' minute) * 1 from dual; select trunc(sysdate) + (interval '1' hour) * 1 from dual; select trunc(sysdate) + (interval '1' day) * 1 from dual; --2.一般写法 select sysdate + 1/24/60/60 from dual; select sysdate + 1/24/60 from dual; select sysdate + 1/24 from dual; select sysdate + 1 from dual;