Oracle 时区转换

select TRUNC(800000000 / 86400 +
             EXTRACT(TIMEZONE_HOUR FROM SYSTIMESTAMP) / 24 +
             TO_DATE('1970-01-01', 'yyyy-mm-dd')) from dual; 
 
 select new_time(sysdate,'PST','GMT') , sysdate  from dual;
 select new_time(sysdate,'PST','GMT')   from dual;
 


Different ways to get the UTC time in Oracle and MSSQL
http://weblogs.asp.net/vikram/archive/2008/05/14/different-ways-to-get-the-utc-time-in-oracle-and-mssql.aspx

http://www.techonthenet.com/oracle/functions/new_time.php