My Requirement is, I have Table in teradata which has a timestamp field in UTC. While soing a select statement i need to display the timestamp field in EST. Need Help.
Do you need daylight saving time?
TS_column AT 'America Eastern'
Without DST:
TS_column AT -5
Related
I can't figure out how to handle the timezone efficiently with dynamodb get operation.
Say my partition primary key and range key (sk) are below, where each record is aggregated data for the whole day done by the user. 2022-09-13 00:00:00 to 2022-09-13 23:23:59
{
pk: 'userId',
sk: '2022-09-13'
}
What is the best approach to store the dates as UTC and fetch based on the client's timezone?
In the current behavior of my program, I'm saving the range key (sk) as UTC date. But if the client's local timezone is +8:00, and when he performs a save operation at 2022-09-14 00:01:00, it will still be stored in the 2022-09-13.
Just store a timestamp (date + time) in UTC instead of the date.
If the client needs data based on the local timezone, you calculate the timestamp of the day start and end in that timezone, shift it to UTC and then do a between query using the utc-start and utc-end.
I have an external data source automatically inserting data into my BigQuery table, this data source includes a timestamp field which does not have a timezone connected to it, however, I know this timestamp is in the Europe/Amsterdam timezone.
The problem here is that when this timestamp is inserted into BigQuery, BigQuery automatically defaults the timestamp to UTC, which it is not. And in my specific case, I want to convert this timestamp to UTC. However because BigQuery already defaulted the timestamp to UTC (while it is actually Europe/Amsterdam), I cannot easily convert it to the actual UTC timezone.
Is there any way to convert this timestamp, which BigQuery thinks is already UTC, to the actual UTC timezone within a query? I can't just give it a -02:00 offset due to Daylight Savings coming into play which changes this offset from 2 hours to only 1 hour depending on the time of year.
Any help would be appreciated, I have been kind of stuck on this :)
An example of the timestamp in BigQuery would be 2022-09-30 01:23:45 UTC
There is probably a better way but this should work
with
input as (select timestamp("2022-09-30 01:23:45 UTC") as ts)
select
ts,
timestamp(replace(cast(ts as string), '+00', " Europe/Amsterdam")) updated_ts
from input
ts
updated_ts
2022-09-30 01:23:45 UTC
2022-09-29 23:23:45 UTC
I am storing one timestamp column in Bigquery table. The source is of CET timestamp. But bigquery is storing it by default in UTC.
How to store it as CET timestamp? otherwise while fetching if also I am doing the timestamp conversion it is manipulating the timestamp value. that I do not want.
Or else I want to convert the value to UTC while fetching but for that I have to make Bigquery understood that the original column is in CET format. How to resolve this?
In the teradata documentation it says:
"Suppose an installation is in the PST time zone and it is New Years Eve, 1998-12-31 20:30 local time.
The system TIMESTAMP WITH TIME ZONE for the indicated time is ' 1999-01-01 04:30-08:00 ' internally."
This does not mesh with my understanding. I figure it ought to be '1999-01-01 04:30+00:00' internally because it should be stored in UTC.
Or, it can be stored as a the local time with a -8 offset, but this example seems to mix the two. Perhaps I am misunderstanding the text?
Not sure if this is an answer, but it's too long for a comment.
That "internal" storage part is very misleading. We don't care how Teradata stores anything internally.
I find this easier to look at using BTEQ, since SQL Assistant doesn't show timezones, at least by default. So, assuming you've logged into BTEQ...
--set session timezone to pst (GMT - 8)
SET TIME ZONE INTERVAL -'08:00' HOUR TO MINUTE ;
create volatile table vt_foo (
ts_w_zone timestamp(0) with time zone,
ts_wo_zone timestamp) on commit preserve rows;
insert into vt_foo
select
cast('1998-12-31 20:30:00' as timestamp(0)),
cast('1998-12-31 20:30:00' as timestamp);
select * from vt_foo;
Currently the two values (with and without tz) will match.
ts_w_zone ts_wo_zone
------------------------- --------------------------
1998-12-31 20:30:00-08:00 1998-12-31 20:30:00.000000
Now let's change the timezone for your session to something else, and look at what we get.
SET TIME ZONE INTERVAL -'03:00' HOUR TO MINUTE ;
select * from vt_foo;
ts_w_zone ts_wo_zone
------------------------- --------------------------
1998-12-31 20:30:00-08:00 1999-01-01 01:30:00.000000
The timestamp with zone is still the same. Displaying it without timezone is automatically converting it to your session timezone, which in this example is GMT -3.
EDIT:
Technically, Teradata is actually storing the time with timezone as GMT (1999-01-01 04:30:00) with the timezone offset (-8). That's where the documentation gets the 1999-01-01 04:30-08:00 value from). But that is not how it displays it.
I am working on a SQLite Database which contains a column which stores value in format yyyy-MM-dd HH:mm:ss. Now I need to create a filter to select rows with filter as this datetime column.
Query:
Select * from tbl_locations where datetime >= '2013-09-11 00:00:00' and datetime <='2013-09-13 00:00:00'
Above query is returning null set despite containing values in this slot(which I verified using select statement without filter.)
Any suggestion how can i get the required data set?
Perhaps this excerpt from the SQLite documentation will help you:
1.2 Date and Time Datatype
SQLite does not have a storage class set aside for storing dates and/or times. Instead, the built-in Date And Time Functions of SQLite are capable of storing dates and times as TEXT, REAL, or INTEGER values:
TEXT as ISO8601 strings ("YYYY-MM-DD HH:MM:SS.SSS").
REAL as Julian day numbers, the number of days since noon in Greenwich on November 24, 4714 B.C. according to the proleptic Gregorian calendar.
INTEGER as Unix Time, the number of seconds since 1970-01-01 00:00:00 UTC.
Applications can chose to store dates and times in any of these formats and freely convert between formats using the built-in date and time functions.
The date and time functions that you can use in your SQL to build your query are documented at http://www.sqlite.org/lang_datefunc.html
Ok, I tested this out in MySQL but hopefully it will work. I had a table that used timestamps, and changed the column to be of type text. Then I tried the following SQL query and got the same results that I normally would (besides trailing decimals)
SELECT timestamp(stock_quote_timestamp)
FROM stock.stock_quote
WHERE stock_quote_timestamp < timestamp('2013-10-07 11:05:30')##high_date
AND stock_quote_timestamp > timestamp('2013-10-03 14:09:03');##low_date;
So basically, just convert your text statements to timestamps so that they compare correctly. Oh, and you'll also need to state what else you're SELECTing, or you could do a compound select statement: SELECT *, timestamp(stock_quote_timestamp)...