如何對時間進行簡單加減運算(轉)

SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';

Session altered.

SQL> select sysdate, sysdate+1/24, sysdate +1/1440, sysdate + 1/86400 from dual;

SYSDATE SYSDATE+1/24 SYSDATE+1/1440 SYSDATE+1/86400
------------------- ------------------- ------------------- -------------------
2008-04-16 21:23:19 2008-04-16 22:23:19 2008-04-16 21:24:19 2008-04-16 21:23:20

SQL> select sysdate,sysdate + 60/(24*60*60) from dual;

SYSDATE SYSDATE+60/(24*60*6
------------------- -------------------
2008-04-16 21:24:40 2008-04-16 21:25:40

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update t_access set IOTIME = to_char(TO_DATE(iotime,'yyyy-MM-dd HH24:mi:ss') +60,'yyyy-MM-dd HH24:mi:ss')