I have been able to convert a TIMESTAMP field that is in UTC to CST using:
SELECT
TIMESTAMP(started_at) AS UTC,
TIMESTAMP_SUB(TIMESTAMP (started_at), INTERVAL 5 HOUR) AS CST
This returns:
ROW
UTC
CST
1
2020-05-17 13:07:22 UTC
2020-05-17 08:07:22 UTC
The second TIMESTAMP displays the correct date and time but UTC still shows. What is the simplest way to replace 'UTC' with 'CST' or, alternatively, remove 'UTC' altogether since I don't need the designation in the field itself?
You can use a plain sql replace function inline
select replace(TIMESTAMP_SUB(TIMESTAMP (started_at), INTERVAL 5 HOUR), 'UTC','') AS CST
The above searches the result of your expression (provided in your question) for 'UTC' and replaces it with nothing ''. You could also replace it with 'CST' as you noted.
Obligatory warning: I believe your query will only be correct half the year as long as DST is observed? You might want to look into sys.time_zone_info and its reference on the MSDN.
My advise is to convert the timestamp to a datetime local value:
select datetime(started_at, 'America/Chicago') as started_at_cst
Note that the time zone is not stored in the data value. Instead, this encodes the value in the string.
If you want to include the time zone value, I have found that the best approach is to use a string (argghh!). The following constructs a string:
format_timestamp('%F %X%z', started_at, 'America/Chicago') as started_at_str
which can be converted easily into a timestamp for date/time calculations:
timestamp(started_at_str)
Related
I have a String in this format: 2018-11-01T00:00:00-07:00 and I would like to convert it to a TIMESTAMP and insert it into a TIMESTAMP column. However, when I insert it, it drops the -07:00 without first converting it to -00:00. How do I ensure that it is converted and stored in Redshift properly?
Here is an example:
select ORIGINAL_DATE, TO_TIMESTAMP(ORIGINAL_DATE,'YYYY-MM-DD HH24:MI:SS') FROM CDW_LANDING.X where id = XXXXXX;
=> 2018-11-01T00:00:00-07:00 2018-10-31 17:00:00
The TO_TIMESTAMP converts it to 2018-10-31 17:00:00 which is what I want. However, when I insert it, it becomes 2018-11-01 00:00:00 and simply drops the -07:00.
Here is the example:
insert into cdw_stage.X (ORIG_DT)
select TO_TIMESTAMP(ORIGINAL_DATE,'YYYY-MM-DD HH24:MI:SS')
from CDW_LANDING.INVOICE where id = XXXXXX;
But when I query it with select ORIG_DT from cdw_landing.X;, it displays 2018-11-01 00:00:00. What I would like to see is 2018-10-31 17:00:00 which is what the TO_TIMESTAMP function should do.
The ORIG_DT in Redshift is in TIMESTAMP format. The input date is in VARCHAR.
How do I get Redshift to save this correctly? I also added postgres tag because Redshift is based off of postgres. Thank you so much!!!
2018-11-01T00:00:00-07:00 is not a timestamp (timestamp without time zone) literal, strictly speaking. It is a timestamptz (timestamp with time zone) literal. This is the root of all pain in your question. The wrong cast to timestamp ignores the offset. The Postgres manual:
In a literal that has been determined to be timestamp without time zone, PostgreSQL will silently ignore any time zone indication. That
is, the resulting value is derived from the date/time fields in the
input value, and is not adjusted for time zone.
Bold emphasis mine.
The use of TO_TIMESTAMP() can't save you. The Redshift manual:
Formats that include a time zone (TZ, tz, or OF) are not supported as input.
(The same is true in Postgres.)
Solution
Cast to timestamptz (or use a column of that type to begin with), the rest should fall in place:
SELECT cast('2018-11-01T00:00:00-07:00' AS timestamptz);
Or:
SELECT '2018-11-01T00:00:00-07:00'::timestamptz;
The manual about casting in Redshift.
When an actual timestamptz is assigned to a timestamp column it is converted according to the current timezone setting of the session automatically. If you want a different target timezone, use the AT TIME ZONE construct. Details:
Ignoring time zones altogether in Rails and PostgreSQL
The related answer is for Postgres, but timestamp handling in Redshift (while differing in many other aspects!) is the same. The Redshift manual:
When converting DATE or TIMESTAMP to TIMESTAMPTZ, DATE or TIMESTAMP
are assumed to use the current session time zone. The session time
zone is UTC by default. For more information about setting the session
time zone, see timezone.
I could appreciate a second pair of eyes on my Postgres syntax.
Database stores timestamp in UTC. I'm trying to convert from UTC to Eastern Daylight Time EDT, but the output is not accurate.
Here's my syntax:
SELECT
to_char(((timestamp AT TIME ZONE 'UTC') AT TIME ZONE 'EDT'), 'MM/DD/YYYY HH24:MI')
FROM table_name
Record TimeStamp:
09/10/2016 12:00
Query Output:
09/10/2016 16:00
Desired Output:
09/10/2016 08:00
Thanks for your assistance.
Saying AT TIMEZONE twice is redundant since it will just convert from whatever the current timezone (which you suggest is UTC) to UTC then to EDT.
The fact that you feel the need to convert it to UTC tells me you're not storing it as a TIMESTAMP WITH TIMEZONE. Check if this is the case. If it is, that's likely your problem. From the docs:
If no time zone is stated in the input string, then it is assumed to be in the time zone indicated by the system's timezone parameter, and is converted to UTC using the offset for the timezone zone.
Basically, if you don't specify, it assumes it's from your current timezone by default, not UTC. It's possible you entered a UTC timestamp and it assumed it was EDT.
I'm trying to read an Oracle TIMESTAMP WITH TIMEZONE from a database in UTC-5 (NY) as UTC.
Oracle is driving me crazy:
SELECT
from_tz(MAX(TIMESTAMPWITHTIMEZONE),'UTC'),
SYS_EXTRACT_UTC(MAX(TIMESTAMPWITHTIMEZONE)),
SYS_EXTRACT_UTC(systimestamp),
SYSTIMESTAMP AT TIME ZONE 'UTC'
FROM TABLE
Results:
SYS_EXTRACT_UTC(systimestamp) gives me: 2013-02-20 14:59:04, which is probably right.
SYSTIMESTAMP AT TIME ZONE 'UTC' gives me: 2013-02-20 15:59:04 which is my own local Berlin - whatever
Now I want to have TIMESTAMPWITHTIMEZONE (TIMESTAMP(6)) as UTC
SYS_EXTRACT_UTC(MAX(TIMESTAMPWITHTIMEZONE)) is 2013-02-20 08:55:01
from_tz(MAX(TIMESTAMPWITHTIMEZONE),'UTC') is 2013-02-20 10:55:01
Srly. Oracle. I want UTC.
Which one is the right one? Or is there a better way?
The functions are different:
SYS_EXTRACT_UTC converts a TIMESTAMP WITH TIMEZONE to a TIMESTAMP (with inferred but absent timezone=UTC).
FROM_TZ converts a TIMESTAMP to a TIMESTAMP WITH TIMEZONE
These functions when applied to a single value will in general return a different result:
SQL> SELECT sys_extract_utc(localtimestamp) ext,
2 from_tz(localtimestamp, 'UTC') from_tz
3 FROM dual;
EXT FROM_TZ
--------------------- ------------------------
2013/02/20 15:34:24 2013/02/20 16:34:24 UTC
In the first case the TIMESTAMP is implicitly given the timezone of the server and then transformed into the equivalent timestamp at the UTC timezone. Note that in general you should stay away from implicit conversions.
In the second case there is no computation between timezones: the FROM_TZ function adds the geographical location to a point in time variable.
By the way there is something missing in your example: you can't apply the FROM_TZ function on a variable of type TIMESTAMP WITH TIMEZONE (tested on 9ir2 and 11ir2):
SQL> select from_tz(systimestamp, 'UTC') from dual;
select from_tz(systimestamp, 'UTC') from dual
ORA-00932: inconsistent datatypes:
expected TIMESTAMP got TIMESTAMP WITH TIME ZONE
Edit following comment:
In your case assuming that your column are of time TIMESTAMP, and knowing that they refer to the NY timezone, you could use the AT TIME ZONE expression to convert to UTC:
SQL> SELECT localtimestamp,
2 from_tz(localtimestamp, 'America/New_York') AT TIME ZONE 'UTC' utc
3 FROM dual;
LOCALTIMESTAMP UTC
--------------------- ------------------------
2013/02/20 17:09:09 2013/02/20 22:09:09 UTC
From Oracle 18c you could use TO_UTC_TIMESTAMP_TZ function:
The TO_UTC_TIMESTAMP_TZ function converts any valid ISO 8601 date represented as a string into a TIMESTAMP WITH TIMEZONE, which can optionally be used as input to the SYS_EXTRACT_UTC function.
SELECT TO_UTC_TIMESTAMP_TZ(col_name)
FROM tab_name;
In Postgres, is it possible to change the default format mask for a timestamp?
right now comes back as
2012-01-03 20:27:53.611489
I would like resolution to minute like this:
2012-01-03 20:27
I know I can do this on individual columns with to_char() as or stripped down with a substr() by the receiving app, but having it formatted correctly initially would save a lot of work and reduce a lot of errors.
In PostgreSQL, The formatting of timestamps is independent of storage. One answer is to use to_char and format the timestamp to whatever format you need at the moment you need it, like this:
select to_char(current_timestamp, 'yyyy-MM-dd HH24:MI:SS.MS');
select to_timestamp('2012-10-11 12:13:14.123',
'yyyy-MM-dd HH24:MI:SS.MS')::timestamp;
But if you must set the default formatting:
Change the postgresql timestamp format globally:
Take a look at your timezone, run this as an sql query:
show timezone
Result: "US/Eastern"
So when you are printing out current_timestamp, you see this:
select current_timestamp
Result: 2012-10-23 20:58:35.422282-04
The -04 at the end is your time zone relative to UTC. You can change your timezone with:
set timezone = 'US/Pacific'
Then:
select current_timestamp
Result: 2012-10-23 18:00:38.773296-07
So notice the -07 there, that means we Pacific is 7 hours away from UTC. How do I make that unsightly timezone go away? One way is just to make a table, it defaults to a timestamp without timezone:
CREATE TABLE worse_than_fail_table
(
mykey INT unique not null,
fail_date TIMESTAMP not null
);
Then if you add a timestamp to that table and select from it
select fail_date from worse_than_fail_table
Result: 2012-10-23 21:09:39.335146
yay, no timezone on the end. But you want more control over how the timestamp shows up by default! You could do something like this:
CREATE TABLE moo (
key int PRIMARY KEY,
boo text NOT NULL DEFAULT TO_CHAR(CURRENT_TIMESTAMP,'YYYYMM')
);
It's a text field which gives you more control over how it shows up by default when you do a select somecolumns from sometable. Notice you can cast a string to timestamp:
select '2012-10-11 12:13:14.56789'::timestamp
Result: 2012-10-11 12:13:14.56789
You could cast a current_timestamp to timestamp which removes the timezone:
select current_timestamp::timestamp
Result: 2012-10-23 21:18:05.107047
You can get rid of the timezone like this:
select current_timestamp at time zone 'UTC'
Result: "2012-10-24 01:40:10.543251"
But if you really want the timezone back you can do this:
select current_timestamp::timestamp with time zone
Result: 2012-10-23 21:20:21.256478-04
You can yank out what you want with extract:
SELECT EXTRACT(HOUR FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 20
And this monstrosity:
SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'EST';
Result: 2001-02-16 20:38:40
In postgres, you can change the default format mask for datetimes - using the set datestyle option; the available options can be found here (see 8.5.2. Date/Time Output).
Unfortunately, all the available options include the number of seconds - you will therefore need to reformat them either in the query or the application code (if applicable).
to_char() is used to create a string literal. If you want a different timestamp value, use date_trunc():
date_trunc('minute', now())
For converting literal input, use to_timestamp():
to_timestamp('2012-01-03 20:27:53.611489', 'YYYY-MM-DD HH24:MI')
This returns timestamptz. Cast to timestamp [without time zone] by appending ::timestamp (which assumes your current timezone setting), or with the AT TIME ZONE construct to define a time zone explicitly.
To my knowledge, there is no setting in PostgreSQL that would trim seconds from timestamp literals by default.
I have a SQL Builder library that direcltly uses ADO.NET. I have a means of creating a select query with a greater-than-or-equal operator, like:
select *
from book
where book.date_created >= {some date}
My issue is that {some date} is going to always be in the UTC time zone, but it's being compared to the book.date_created column which is a TIMESTAMP(6) WITH TIME ZONE column, which will not be in the UTC timezone.
I can execute the query, but my results are off becuaes of timezone comparisons. My query is for all books where the date_created >= x, but some of the results returned are not greater than x because after subtracting 5 hours for the time zone, they are now less than x. The IDataRecord DateTime fields returned are converted to UTC using DateTime.SpecifyKind()
Can I form my query such that it interprets book.date_created in the UTC timezone?
Note: While I'd love to change my Oracle DB columns to not specify timezones, changing table structures is not something I can do.
Edit:
Currently, {some date} is a SQL Parameter. It's backing datatype is a DateTime with UTC as the timezone. As a parameter, it is a TimestampWithTZ. The Value of the parameter is a DateTime with the kind specified as UTC as well.
Update:
The issue seems to be related to my results set from the IDataRecord. When I pull DateTimes off, I use DateTime.SpecifyKind() to put them in UTC mode. The problem is, the date times come out as DateTimeKind.Unspecified. When converting from Unspecified to UTC, it just drops the timezone and declares it is UTC without changing the underlying value. I'm not sure how to have the IDataRecord pull in the TimeZone value.
You need to use the FROM_TZ function that transforms a TIMESTAMP into a TIMESTAMP WITH TIME ZONE. For example, if you know that your variable is in UTC time (+0:00):
SELECT *
FROM book
WHERE date_created >= from_tz(<timestamp>, '+0:00');
Here's a sample script that shows the behaviour you describe (your local time zone should be set to +1:00):
CREATE TABLE t (tz TIMESTAMP(6) WITH TIME ZONE);
INSERT INTO t VALUES
(to_timestamp_tz('20000101 00:00:00 +1:00','yyyymmdd hh24:mi:ss tzh:tzm'));
INSERT INTO t VALUES
(to_timestamp_tz('20000101 00:00:00 -1:00','yyyymmdd hh24:mi:ss tzh:tzm'));
-- This will return two values instead of one
SELECT *
FROM t
WHERE tz >= to_timestamp('20000101 00:00:00', 'yyyymmdd hh24:mi:ss');
-- This query will return only one row
SELECT *
FROM t
WHERE tz >= from_tz (to_timestamp('20000101 00:00:00',
'yyyymmdd hh24:mi:ss'), '+0:00');
below links will help you.
Datetime Datatypes and Time Zone Support
TIMESTAMP WITH TIME ZONE Data Type
Write Time Zone Aware Code in Oracle
ORACLE timezone summary
Oracle Date and Time data types