不同时区的查询
select n.tzname, n.tzabbrev, tz_offset(n.tzname) from v$timezone_names n;
不同时区的转换方法
时区转换的语法 at time zone
select systimestamp, systimestamp at time zone sessiontimezone from dual;
select from_tz(to_timestamp('2008/03/28 16:00:00'), '+08:00') at time zone '-07:00' from dual;
select to_timestamp_tz('2008/03/28 16:00:00 +08:00') at time zone 'US/Mountain' from dual;
-- 如果仅仅转换到UTC (GMt),使用 sys_extract_utc
select systimestamp,
sys_extract_utc(systimestamp) utc,
(to_timestamp_tz(to_char(systimestamp)) at time zone '00:00') manually_utc
from dual;