I am trying to fetch the result of a table with timezone datatype field in TD 14 SQL assistant.
lock row for access sel * from uk_istl_rtm_data.rtim_message_event_history
where substr(message_name,1,5) in ('G1874','G1906','G1571')
and response_dttm BETWEEN '2021-03-30 00:00:00' AND '2021-03-30 23:59:59'
This query is fetching records from 29th March 23:00 after daylight savings.
I have checked the TimeDateWZControl of DBScontrol and its 3.
I am looking for a way in which I can handle this timezone issue data at query level only.
Thanks all for the suggestion. I casted it as below and it worked.
SET TIME Zone 'europe central';
SELECT
CAST(response_dttm AS TIMESTAMP(6) FORMAT 'Y4-MM-DDBHH:MI:SSBZ') AT 'europe central'
from uk_istl_rtm_data.rtim_message_event_histor
where response_dttm BETWEEN '2021-03-30 00:00:00' AND '2021-03-30 23:59:59';
Related
cloud somebody explain to me why casting timestamp to date in psql gives me wrong value? I have in my db stored time stamp value 2016-12-04 00:05:09.748000 and my machine time is in UTC, and datatype in psql is TIMESTAMP WITH TIME ZONE. If I did this,
orders.completed::date
it gives me 2016-12-03. Problem is that if i have some orders around midnight aggregate functions gives me wrong values. Is there some way how to solve it? I would appreciate any help!
Try this :
(orders.completed::timestamp at time zone 'UTC' at time zone 'America/Los_Angeles')::date;
You need to insert your timezone in query
Hm, I can't reproduce it:
b=# set timezone to "GMT+10";
SET
b=# create table edge (t timestamptz);
CREATE TABLE
b=# insert into edge select now();
INSERT 0 1
b=# select t::date, t from edge;
t | t
------------+-------------------------------
2016-12-08 | 2016-12-08 00:18:30.740132-10
(1 row)
I'm working on an app in which users can log in and select a site which may be in a different time zone. Because the app is showing data that is relevant to that site I've decided to set the default timezone for the app to be the site timezone via NSTimeZone.setDefaultTimeZone. This works great except when I select data out of our sqlite db via FMDB (I don't think FMDB has anything to do with it) and use strftime with 'localtime'. While our data is stored by the minute in UTC using epochs, we often need to show summations by day, weekday or month in the local time zone. For example to get averages by weekday:
select strftime('%w',datetime(epoch,'localtime')),avg(value)
from values
where siteId = 'x'
group by 1
order by 2 desc
The 'localtime' that it's using is the system local time and not the default time zone for the app where all NSDate calls respect the default time zone. There does not to be any other timezone options for strftime other than localtime and UTC and the current work arounds are pretty slow requiring multiple SQL roundtrips where this should easily be handled in 1 query as above.
Can anyone tell me how sqlite on iOS determines 'localtime'? Is there a way to force it to use a different i.e. defaultTimeZone?
As you have seen, SQLite doesn't use NSDate or the app's local timezone. The datetime function converts with a Modifier. Say you had a DB that stores as GMT (I think this is the case for your app):
sqlite> create table mytable (id int, time datetime);
sqlite> insert into mytable values (1, CURRENT_TIMESTAMP);
sqlite> select time from mytable;
2016-06-24 19:05:36 <- THIS IS GMT
sqlite> select datetime(time, 'localtime') from mytable;
2016-06-24 15:05:36 <- THIS IS LOCAL TIME
In this example (and yours) 'localtime' is the Modifier. From the sqlite docs:
Modifiers
The time string can be followed by zero or more modifiers that alter
date and/or time. Each modifier is a transformation that is applied to
the time value to its left. Modifiers are applied from left to right;
order is important. The available modifiers are as follows.
NNN days
NNN hours
NNN minutes
NNN.NNNN seconds
NNN months
NNN years
start of month
start of year
start of day
weekday N
unixepoch
localtime
utc
So you cannot directly convert to the local value. However, because you can use these modifers your app can get your local GMT offset from NSDate:
if let myZone = NSTimeZone(abbreviation: "EST")
{
NSTimeZone.setDefaultTimeZone(myZone)
var offset = (myZone.secondsFromGMT)/3600 as Int
var offsetModifer = "\(offset) hours"
}
Then you can execute your sqlite query as so (building the query using offsetModifer which translates to -4 hours in the example here:
sqlite> select datetime(time, '-4 hours') from mytable;
2016-06-24 15:05:36
I am using Esper & I need to filter events by their timestamp. The events come from an external source.
The challenge is that the cutoff instant is at a different timezone than the events` timestamp, e.g. the cutoff instant is at 3:30 CET (e.g. Prague time) while the timestamp field of the event is at UTC.
This poses a problem when the timezone shifts to Daylight Savings Time, because the cutoff instant needs to be modified in the query. E.g. in this case, if the cutoff instant is 3:30 CET, during winter time it would be on 2:30 UTC and during DST it would be on 1:30 UTC. It means that I have to change the query when the time shifts into and out of DST.
This is the current query:
SELECT *
FROM my_table
WHERE timestamp_field.after( timestamp.withtime(2,30,0,0) )
I would like to have a robust solution that will save me the hassle of changing the cutoff timestamp queries every few months. Can I add the timezone to the query statement itself? Is there any other solution?
It may help to add an event property to the event that represents UTC time i.e. normalize the event timestamp to UTC and use the normalized property instead.
The query could also use a variable instead of the hardcoded numbers. Another option would perhaps be changing Esper source to take in a timezone for some func.s
After struggling unsuccessfully with trying ot do it in the WHERE caluse or using a Pattern, I managed to solve the issue using a [Single-Row Function plugin][1].
I pass the plugin function the cutoff hour, timezone & event timezone and compute the cutoff hour in the event's timezone.
My query changed to:
SELECT *
FROM my_table
WHERE timestamp_field.after( timestamp.withtime(
eventTZHour(2, 'UTC', 'Europe/Prague'), 30, 0, 0) )
I added the Java implementation in a class:
public class EsperPlugins {
public int eventTZHour(int hour, String eventTZ, String cutoffTZ) {
// return tz calculations
}
}
and finally registered the plugin in esper.cfg.xml:
<esper-configuration>
<plugin-singlerow-function name="eventTZHour"
function-class="EsperPlugins"
function-method="eventTZHour"/>
</esper-configuration>
[1]: http://www.espertech.com/esper/release-5.2.0/esper-reference/html/extension.html#custom-singlerow-function from esper's docs
I'm trying to figure out if it's possible to group data by date from a specific time of a date to a time in next date.
I've a bills table in Postgresql database with the following columns:
id serial NOT NULL,
bill_amount double precision,
tax_amount double precision,
discount double precision,
grand_total double precision,
created_at timestamp without time zone NOT NULL,
updated_at timestamp without time zone NOT NULL
I want group by clause like from date 2015-09-12 06:00:00.00000 to date 2015-09-13 06:00:00.00000, means all records less than 2015-09-13 06:00:00.00000 and greater than 2015-09-12 06:00:00.00000 will be considered as data of 12th September. So if I want to get the data of a month with group by date, is it possible?
In Postgresql you could use this as your grouping expression:
date_trunc('day',created_at-interval '6h')
(assuming created_at is the field you are wanting to group by).
I am no Rails expert, but glancing through the documentation I formed the opinion you might be able to get it to issue such SQL with something like
Bills.select("date_trunc('day',created_at-interval '6h') as day")
.group("date_trunc('day',created_at-interval '6h')")
Incidentally, I am guessing the reason you want the days to run from 06:00 to 06:00 is that the timezones of the date columns are not aligned - you would be better off to either ensure that the data stored in these columns is aligned so that days run from 00:00 - 00:00, or to use timestamp with timezone as the type of these columns if the table will store data from multiple time zones.
Background
Article model with default created_at column
Rails config.time_zone = 'Warsaw'
I've got an article with created_at = local time 2012-08-19 00:15 (2012-08-18 22:15 in UTC).
Goal
To receive all articles created in 2012-08-19 (in local time).
My (not working properly) solution
Article.where(
"date_trunc('day', created_at AT TIME ZONE '#{Time.zone.formatted_offset}')
= '#{Date.civil(2012, 8, 19)}'"
)
Which generates SQL:
SELECT "articles".* FROM "articles"
WHERE (date_trunc('day', created_at AT TIME ZONE '+01:00') = '2012-08-19')
And returns an empty set. But if I run the same query in psql it returns an article ... which confuses me.
Question
What am I doing wrong and how to fix it?
Goal: To receive all articles created in 2012-08-19 (in local time).
'+01:00' (like you use it) is a fixed time offset and cannot take DST (Daylight Saving Time) into account. Use a time zone name for that (not an abbreviation). These are available in PostgreSQL:
SELECT * FROM pg_timezone_names;
For Warsaw this should be 'Europe/Warsaw'. The system knows the bounds for DST from its stored information and applies the according time offset.
Also, your query can be simplified.
As created_at is a timestamp [without time zone], the values saved reflect the local time of the server when the row was created (saved internally as UTC timestamp).
There are basically only two possibilities, depending on the time zone(s) of your client.
Your reading client runs with the same setting for timezone as the writing client: Just cast to date.
SELECT *
FROM articles
WHERE created_at::date = '2012-08-19';
Your reading client runs with a different setting for timezone than the writing client: Add AT TIME ZONE '<tz name of *writing* client here>'. For instance, if that was Europe/Warsaw, it would look like:
...
WHERE (created_at AT TIME ZONE 'Europe/Warsaw')::date = '2012-08-19';
The double application of AT TIME ZONE like you have it in your posted answer should not be necessary.
Note the time zone name instead of the abbreviation. See:
Time zone names with identical properties yield different result when applied to timestamp
If you span multiple time zones with your application ..
.. set the column default of created_at to now() AT TIME ZONE 'UTC' - or some other time zone, the point being: use the same everywhere.
.. or, preferably, switch to timestamptz (timestamp with time zone).
Linked answer helped. I have to run following query:
SELECT *
FROM articles
WHERE (created_at AT TIME ZONE 'UTC' AT TIME ZONE 'CEST')::date = '2012-08-19';
This question would need the exact definition of the column created_at (what data type exactly?)
Rails always creates created_at column as timestamp without time zone. So I have to make the first AT TIME ZONE 'UTC' to say dbms that this timestamp is at UTC, and the second one to display date at CEST zone.