In my code when I save one date as todays date in Eastern Time zone, It gets displayed correctly when we view it.But In Pacific time zone, It is showing previous date ie of yesterdays date. We are storing date in Oracle as a date field.
Any special coding required to fecth corect date in Pacific time?
Dates do not have a time zone - so when you store dates from different time zone you need to make sure that you convert them to be in the same time zone.
CREATE TABLE table_name( id INT, value DATE );
INSERT INTO table_name VALUES( 1, TIMESTAMP '2016-07-07 23:00:00 PST' AT TIME ZONE 'UTC' );
INSERT INTO table_name VALUES( 1, TIMESTAMP '2016-07-07 23:00:00 EST' AT TIME ZONE 'UTC' );
Then:
SELECT id,
value AS utc,
CAST(
FROM_TZ( CAST( value AS TIMESTAMP ), 'UTC' ) AT TIME ZONE 'EST'
AS DATE
) AS EST,
CAST(
FROM_TZ( CAST( value AS TIMESTAMP ), 'UTC' ) AT TIME ZONE 'PST'
AS DATE
) AS PST
FROM table_name t;
Outputs:
ID UTC EST PST
-- ------------------- ------------------- -------------------
1 2016-07-08 06:00:00 2016-07-08 01:00:00 2016-07-07 23:00:00
2 2016-07-08 04:00:00 2016-07-07 23:00:00 2016-07-07 21:00:00
Related
I am using Oracle 19c.
I need to convert dates from GMT to EST and EDT.
I am using the following approach:
1. Get the destination time zone abbreviation for the p_date variable:
DEFINE p_date TO_DATE('03/11/2013 02:22:21', 'MM/DD/YYYY HH24:MI:SS');
SELECT TO_CHAR(FROM_TZ(CAST (&p_date AS TIMESTAMP), 'America/New_York'), 'TZD') INTO v_tzabbrev FROM DUAL;
Where:
p_date: is the date to be converted.
v_tzname: is the time zone name, such as America/New_York
v_tzabbrev: is the time zone abbreviation, such as 'EDT' or "EST" based on whether the date is during Daylight Saving Time or not
2. Convert the p_date using the time zone abbreviation obtained in #1
SELECT NEW_TIME(p_date, 'GMT', v_tzabbrev) INTO v_date FROM DUAL;
This seems to work. But, I believe the flaw is that it is using the GMT date to determine the destination time zone abbreviation, which is inaccurate.
For example, if p_date, in UTC, is '03/11/2013 02:22:21' and I need to convert it to 'America/New_York', Step #1 would return 'EDT', but this date in Eastern was actually "03/10/2013 21:22:21", which was before Daylight Saving started. So, it should actually be converted using "EST".
Daylight saving time in '2013 began at 2 a.m. on Sunday, March 10.
So, it seems that I need a way to take the GMT value and determine its new date in Eastern first, then apply additional logic based on whether that new date is EDT or EST.
Any assistance is appreciated.
You can define p_date directly as UTC time:
DEFINE p_date TO_TIMESTAMP_TZ('03/11/2013 02:22:21 UTC', 'MM/DD/YYYY HH24:MI:SS TZR');
SELECT TO_CHAR((&p_date AT TIME ZONE 'America/New_York'), 'TZD')
INTO v_tzabbrev
FROM DUAL;
Or in the statement:
DEFINE p_date TO_DATE('03/11/2013 02:22:21', 'MM/DD/YYYY HH24:MI:SS');
SELECT TO_CHAR((FROM_TZ(CAST(&p_date AS TIMESTAMP), 'UTC') AT TIME ZONE 'America/New_York'), 'TZD')
INTO v_tzabbrev
FROM DUAL;
Another possibility is to use SESSIONTIMEZONE implicitly, although I don't recommend this:
DEFINE p_date TO_DATE('03/11/2013 02:22:21', 'MM/DD/YYYY HH24:MI:SS');
ALTER SESSION SET TIME ZONE = 'UTC';
SELECT TO_CHAR((CAST(&p_date AS TIMESTAMP WITH TIME ZONE) AT TIME ZONE 'America/New_York'), 'TZD')
INTO v_tzabbrev
FROM DUAL;
"Daylight saving time in '2013 began at 2 a.m. on Sunday, March 10."
... which is correct, and you can see that happening with the UTC equivalent date/time as:
-- get New York DST start time as UTC
with cte (ts) as (
select timestamp '2013-03-10 01:59:59 America/New_York' from dual
union all
select timestamp '2013-03-10 03:00:00 America/New_York' from dual
)
select ts, to_char(ts, 'TZD') as tzd, ts at time zone 'UTC' as ts_utc
from cte
TS
TZD
TS_UTC
2013-03-10 01:59:59 AMERICA/NEW_YORK
EST
2013-03-10 06:59:59 UTC
2013-03-10 03:00:00 AMERICA/NEW_YORK
EDT
2013-03-10 07:00:00 UTC
but this date in Eastern was actually "03/10/2013 21:22:21", which was before Daylight Saving started.
No, it isn't, it's after DST started.
So, it should actually be converted using "EST".
No, it shouldn't. I'm afraid the premise of your question is wrong.
The conversion you are doing is getting the correct result:
-- get UTC timestamp as New York
with cte (ts) as (
select timestamp '2013-03-11 02:22:21 UTC' from dual
)
select ts as ts_utc, ts at time zone 'America/New_YORK' as ts, to_char(ts at time zone 'America/New_York', 'TZD') as tzd
from cte
TS_UTC
TS
TZD
2013-03-11 02:22:21 UTC
2013-03-10 22:22:21 AMERICA/NEW_YORK
EDT
fiddle
2013-03-11 02:22:21 UTC is after 2013-03-10 01:59:59 America/New_York, as it is the following day in UTC, and 19 hours after the New York DST switch occurred. In other words, 2013-03-11 02:22:21 UTC is 19 hours after 2012-03-10 07:00:00 UTC, which is the UTC equivalent of the EDT start-time from the first query above.
You seem to be confusing the date in your UTC value with the date that DST was applied in the USA that year.
Because the NEW_TIME() function is limited, I would prefer to use FROM_TZ and AT TIME ZONE, as Wernfried showed.
We are trying to perform arithmetic on a date. We are trying to add 1 day (24 hours) Here's a basic example...
select to_date('2018-10-06 22:00:00') + 1 from dual;
The result we get back from this is as follows...
2018-10-07 22:00:00
That seems good on paper, however we are in the Sydney timezone and during that interim period daylight savings occurs so the time should like something more like this...
2018-10-07 23:00:00
So I suppose my question is, when doing arithmetic in oracle is it possible to take into consideration daylight savings time. One idea was to convert the initial date to UTC and convert back to SYDNEY time, but it seems like a complicated solution that might already be handled by oracle functionality somewhere.
Cheers
You can't really do it directly with a date as those are not timezone aware.
You can start with a timestamp with time zone, e.g. as a timestamp literal:
select timestamp '2018-10-06 22:00:00 Australia/Sydney' + interval '1' day
from dual;
TIMESTAMP'2018-10-0622:00:00AUSTRALIA/SYDNEY'+
----------------------------------------------
2018-10-07 23:00:00.000000000 AUSTRALIA/SYDNEY
which you can cast back to a date if you want to discard that information:
select cast(timestamp '2018-10-06 22:00:00 Australia/Sydney' + interval '1' day as date)
from dual;
CAST(TIMESTAMP'2018
-------------------
2018-10-07 23:00:00
If you're starting from a date, e.g. in a table column, you can cast that to a timestamp and specify the time zone:
with your_table (your_date) as (
select to_date('2018-10-06 22:00:00') from dual
)
select from_tz(cast(your_date as timestamp), 'Australia/Sydney') + interval '1' day
from your_table;
FROM_TZ(CAST(YOUR_DATEASTIMESTAMP),'AUSTRALIA/
----------------------------------------------
2018-10-07 23:00:00.000000000 AUSTRALIA/SYDNEY
and optionally cast back to date again to discard the fractional seconds and time zone information.
If your session time zone is Sydney then you could let that be set implicitly by casting to timestamp with time zone instead:
with your_table (your_date) as (
select to_date('2018-10-06 22:00:00') from dual
)
select cast(your_date as timestamp with time zone) + interval '1' day
from your_table;
but it's generally better not to assume anything about the session environment that will run your code.
When the clocks go back at the end of DST you can specify which of the two possible values of times between 02:00 and 03:00 you mean by including a DST indicator:
alter session set nls_timestamp_tz_format = 'YYYY-MM-DD HH24:MI:SS TZH:TZM';
select timestamp '2018-04-01 01:00:00 Australia/Sydney AEDT' from dual;
TIMESTAMP'2018-04-0101:00:
--------------------------
2018-04-01 01:00:00 +11:00
select timestamp '2018-04-01 02:00:00 Australia/Sydney AEDT' from dual;
TIMESTAMP'2018-04-0102:00:
--------------------------
2018-04-01 02:00:00 +11:00
select timestamp '2018-04-02 02:00:00 Australia/Sydney AEST' from dual;
TIMESTAMP'2018-04-0202:00:
--------------------------
2018-04-02 02:00:00 +10:00
select timestamp '2018-04-01 03:00:00 Australia/Sydney AEST' from dual;
TIMESTAMP'2018-04-0103:00:
--------------------------
2018-04-01 03:00:00 +10:00
Although for me this only seems to work in 12.2.0.1; in earlier versions AEST/AEDT aren't recognised (though EST is). I'm not sure if that's just down the time zone file version - my 12.2 instance have version 26.
Going the other way if you have times that appear to be in the hour that doesn't exist when the clocks go forward at the start of DST, there isn't much you can do about it as they are invalid. If you populate fields using sysdate and the server is set to Sydney, or current_date and the session is, then that shouldn't happen. Dates created with to_date() could be in that window, but then you probably need to figure out why and stop that happening.
I have to create convert a datetime as UTC into localtime (GMT/BST)
The dates in the database are UTC AND the database is set to UTC.
I believe I can get the offset between UTC and (say) BST using TZ_OFFSET, but how can I then use that to convert the UTC datetime into a BST datetime?
So, for example, if the database (UTC) datetime is
'2018-04-03 14:30:00'
And the offset is '+01:00'
I would expect the result to be
'2018-04-03 15:30:00'
If there an elegant way of doing this? Rather than using grungy arithmetic (which then has to take into account midnight, end of month, end of year etc.)
Thanks
Use FROM_TZ to create a TIMSTAMP WITH TIME ZONE, then the conversion is very simple, for example:
FROM_TZ({your column}, 'UTC') AT TIME ZONE 'Europe/London'
As you can see in the documentation:
Example of Converting Time Zones With the AT TIME ZONE Clause:
SELECT FROM_TZ(CAST(TO_DATE('1999-12-01 11:00:00',
'YYYY-MM-DD HH:MI:SS') AS TIMESTAMP), 'America/New_York')
AT TIME ZONE 'America/Los_Angeles' "West Coast Time"
FROM DUAL;
West Coast Time
----------------------------------------------------------
01-DEC-99 08.00.00.000000 AM AMERICA/LOS_ANGELES
So, applied to your case scenario:
SELECT FROM_TZ(CAST(TO_DATE('2018-04-03 14:30:00',
'YYYY-MM-DD HH24:MI:SS') AS TIMESTAMP), 'UTC')
AT TIME ZONE 'GMT' "Greenwich Mean Time"
FROM DUAL;
Greenwich Mean Time
----------------------------------------------------------
03-APR-18 02.30.00.000000 PM GMT
You can get the list of available timezones with:
SELECT tzname, tzabbrev FROM V$TIMEZONE_NAMES;
If you have a table YOUR_TABLE with a column some_timestamp:
create table YOUR_TABLE (
some_timestamp timestamp
);
/
insert into YOUR_TABLE (
SOME_TIMESTAMP
) values (
CAST(TO_DATE('2018-04-03 14:30:00', 'YYYY-MM-DD HH24:MI:SS') AS TIMESTAMP)
);
Then you can run:
select
SOME_TIMESTAMP,
FROM_TZ(SOME_TIMESTAMP, 'UTC') AT TIME ZONE 'GMT' "Greenwich Mean Time",
FROM_TZ(SOME_TIMESTAMP, 'UTC') AT TIME ZONE 'Europe/London' "London Time"
from YOUR_TABLE;
SOME_TIMESTAMP Greenwich Mean Time London Time
----------------------------------------------------------
03-APR-18 02.30.00.000000 PM 03-APR-18 02.30.00.000000 PM GMT 03-APR-18 03.30.00.000000 PM EUROPE/LONDON
And if you are absolutely sure that your server is in UTC, as well as the timestamps introduced, then you can skip that UTC conversion part:
select
SOME_TIMESTAMP,
SOME_TIMESTAMP AT TIME ZONE 'GMT' "Greenwich Mean Time",
SOME_TIMESTAMP AT TIME ZONE 'Europe/London' "London Time"
from YOUR_TABLE;
it should be pretty simple::
select datetimecolumn + INTERVAL '1' HOUR from mytable
hope i understand your requirement correctly.
I have to convert UTC time to some specific time zone, I have converted the sysdate to UTC,now I want to convert it to time zone specific, This is how I am converting sysdate to UTC
select cast(sys_extract_utc(systimestamp) as DATE) from dual;
I tried writing +5 before from keyword,but its returning the date after 5 days.
select cast(sys_extract_utc(systimestamp) as DATE)+5 from dual;
I have get the timezone offset with below query, but I have clue to use this in above query
SELECT TZ_OFFSET('US/Eastern') FROM DUAL;
How can I convert the UTC time to some timezone offset,something like below
select cast(sys_extract_utc(systimestamp) as DATE) from dual where TZ_OFFSET=+5;
You can get the current UTC time using:
SELECT CAST( SYSTIMESTAMP AT TIME ZONE 'UTC' AS DATE )
FROM DUAL;
You can reverse the process to change a UTC DATE to a TIMESTAMP WITH TIME ZONE at +04:00 using:
SELECT FROM_TZ( CAST( your_date AS TIMESTAMP ), 'UTC' ) AT TIME ZONE '+04:00'
FROM your_table
Trying to add on the time zone offset would give you problems with daylight savings adjustments.
You can use the at time zone syntax to specify a conversion, but you don't need to convert to UTC first. If you do you might not get what you expect, without taking an extra step:
select systimestamp as sys_ts,
sys_extract_utc(systimestamp) as utc_ts,
sys_extract_utc(systimestamp) at time zone 'US/Eastern' as edt_ts
from dual;
SYS_TS UTC_TS EDT_TS
------------------------------ ----------------------- ----------------------------------
2017-10-05 11:30:41.023 +01:00 2017-10-05 10:30:41.023 2017-10-05 05:30:41.023 US/EASTERN
That says the time in New York is 05:30, when it's actually 06:30 at time of writing.
The sys_extract_utc function gives you the UTC equivalent of your system time, but with on embedded time zone info - it's a plain timestamp, not a timestamp with time zone. So when you adjust it, it's implicitly converted to the system time zone with no adjustment, leaving you with the wrong actual time.
You can specify that the extracted value is UTC using the from_tz() function:
select systimestamp as sys_ts,
sys_extract_utc(systimestamp) as utc_ts,
from_tz(sys_extract_utc(systimestamp), 'UTC') at time zone 'US/Eastern' as edt_ts
from dual;
SYS_TS UTC_TS EDT_TS
------------------------------ ----------------------- ----------------------------------
2017-10-05 11:30:41.144 +01:00 2017-10-05 10:30:41.144 2017-10-05 06:30:41.144 US/EASTERN
But you don't need to do that much work, you can just take the original time zone-aware systimestamp value and apply at time zone directly to that:
select systimestamp as sys_ts,
systimestamp at time zone 'US/Eastern' as edt_ts
from dual;
SYS_TS EDT_TS
------------------------------ ----------------------------------
2017-10-05 11:30:41.271 +01:00 2017-10-05 06:30:41.271 US/EASTERN
Which you can then cast to a date data type if that is a requirement:
cast(from_tz(sys_extract_utc(systimestamp), 'UTC') at time zone 'US/Eastern' as date)
or more simply:
cast(systimestamp at time zone 'US/Eastern' as date)
Hi I have a date field (Open_Time) containing timestamp data. The times in this column are in UTC. I want to select that column and convert it to EST and insert it into another table. I want it to be EST for the time at the original timestamp (take into account daylight savings time based on what day month and year it was). I have been reading about the various timezone functions in oracle but most seem to focus on altering the database's timezone which I don't need to do. The (Open_Time) field is always recorded in UTC.
BLUF: I need to select a time_stamp field (Open_Time) that was recorded according to UTC time and convert it to what EST was at the time of (Open_Time). Thanks.
If you are using the TIMESTAMP WITH TIME ZONE data type:
Oracle Setup:
CREATE TABLE Table_Name (
open_time TIMESTAMP WITH TIME ZONE
);
INSERT INTO Table_Name VALUES ( SYSTIMESTAMP AT TIME ZONE 'UTC' );
Query:
SELECT open_time AT TIME ZONE 'UTC' AS utc,
open_time AT TIME ZONE 'EST' AS est
FROM Table_Name;
Output:
UTC EST
----------------------------------- -----------------------------------
02-MAR-16 22.41.38.344809000 UTC 02-MAR-16 17.41.38.344809000 EST
or if you are just using the TIMESTAMP data type:
Oracle Setup:
CREATE TABLE Table_Name (
open_time TIMESTAMP
);
INSERT INTO Table_Name VALUES ( SYSTIMESTAMP );
Query:
SELECT CAST( open_time AS TIMESTAMP WITH TIME ZONE ) AT TIME ZONE 'UTC' AS utc,
CAST( open_time AS TIMESTAMP WITH TIME ZONE ) AT TIME ZONE 'EST' AS est
FROM Table_Name;
Output:
UTC EST
----------------------------------- -----------------------------------
02-MAR-16 22.41.38.344809000 UTC 02-MAR-16 17.41.38.344809000 EST