Oracle 时间问题，请指教

Question

SQL> select to_char(to_date('20050705000117','yyyymmddhh24miss')-6/24/3600,'yyyy
mmddhh24miss') from dual;TO_CHAR(TO_DAT
--------------
20050705000111SQL>

Answer 1

1.SQL> select to_date('20050705000117','yyyymmddhh24miss') - 1/24/60/60*6 from dual;TO_DATE('20050705000117','YYYY
------------------------------
2005-7-5 0:01:11
2.SQL> select to_date('20050705000117','yyyymmddhh24miss') - interval '6' second from dual;TO_DATE('20050705000117','YYYY
------------------------------
2005-7-5 0:01:11
3.SQL> select to_date('20050705000117','yyyymmddhh24miss') - numtodsinterval(6,'second') from dual;TO_DATE('20050705000117','YYYY
------------------------------
2005-7-5 0:01:11

Answer 2

select to_date('20050705000117','YYYYMMDDHH24MISS'),to_date('20050705000117','YYYYMMDDHH24MISS')-6/60/60/24 from dual>2005/07/05 0:01:17     2005/07/05 0:01:11