This query displays count Actions grouped by day of the week.
select count(*) c,
date_part('dow', "updatedAt" at time zone 'Europe/Paris') dow
from "Action" date_part('dow', "updatedAt" at time zone 'Europe/Paris')
Days are displayed as number. Is there a way to display it as text? Does PostgreSQL has such a function?
Use to_char() to format a date or timestamp value as text. You can use Day to display the day's name (e.g. Tuesday)
select count(*) c,
to_char("updatedAt" at time zone 'Europe/Paris', 'Day') dow
from "Action"
group by to_char("updatedAt" at time zone 'Europe/Paris', 'Day')
IF you want text format use ::TEXT at the end. in future you can use other like ::DATE, ::TIMESTAMP, ::DECIMAL...
date_part('dow', "updatedAt" at time zone 'Europe/Paris')::TEXT dow
Related
to_date('30/03/2022', 'DD/MM/YYYY')
Underlined, as hours are not specified, that means that hour is '00:00'
I would like to specify that this is for Europe/Paris time zone region.
Can you help me set-up this ?
Thanks
A DATE data type has the components: year, month, day, hour, minute and second. It ALWAYS has those components and NEVER stores anything else (such as a time zone); so it is impossible to store a time zone in a DATE data type.
A TIMESTAMP data type has the components: year, month, day, hour, minute and second and, optionally, can store fractional seconds.
A TIMESTAMP WITH TIME ZONE data type has the components: year, month, day, hour, minute, second and time zone and, optionally, can store fractional seconds information.
Therefore, if you want to store a time zone then you should use TIMESTAMP WITH TIME ZONE and not DATE.
Your code would then be:
TO_TIMESTAMP_TZ('30/03/2022 Europe/Paris', 'DD/MM/YYYY TZR')
or using a timestamp literal:
TIMESTAMP '2022-03-30 00:00:00 Europe/Paris'
or, if you want to pass in your date in that format and add the time zone in a two-step process:
FROM_TZ(TO_TIMESTAMP('30/03/2022', 'DD/MM/YYYY'), 'Europe/Paris')
db<>fiddle here
I am working with time data that is currently stores in UTC but I want it to be in PST, which is 8 hours behind. I have a pretty lengthy and involved query, but the only thing I am interested in is the time right now so I have included those parts. I want to convert the times to PST and then group by the date for the last week of data. The query has the following structure:
select
date_trunc('day', time1) AT TIME ZONE 'US/Pacific'
...
where
time1 AT TIME ZONE 'US/Pacific' > now() AT TIME ZONE current_setting('TimeZone') - INTERVAL '168 HOURS'
...
group by date_trunc('day', time1)
This results in the following time groupings. From my understanding, it groups from the 0:00 UTC, which is 16:00 in PST. However, I want the groupby to start at 0:00 PST. How do I do this? Right now, the counts in each group are misleading for each day because they go from 4 pm to 4 pm instead of 12 am to 12 am. For example, Sundays have uncharacteristically high counts because Sunday includes part of Monday's data in the groupby. I would appreciate any input to fix this issue. Thank you.
The answer depends on whether it is a timestamp with time zone or one without:
If it's a timestamp with time zone, you can convert to PST with select time1 AT TIME ZONE 'US/Pacific' and get the date with select date_trunc('day', time1 AT TIME ZONE 'US/Pacific')
If it's a timestamp without time zone stored in UTC that you want to convert, you first have to tell PostgreSQL to interpret it as UTC, then convert it, like so: select (time1 AT TIME ZONE 'Z') AT TIME ZONE 'US/Pacific' and of course you can get the date with select date_trunc('day', (time1 AT TIME ZONE 'Z') AT TIME ZONE 'US/Pacific')
In either case you have to convert time zones before truncating to the day level or you may end up with inaccurate results.
I have a column called login_timestamp, which is of type TIMESTAMP WITH TIME ZONE.
To retrieve the month for this timestamp, I would do: EXTRACT(MONTH FROM login_timestamp).
However, I would like to retrieve the month for a specific time zone (in my case, Pakistan), but can't figure out how to do that.
Documentation for this is under Date/Time Functions and Operators. Search that page for "at time zone".
select extract(month from login_timestamp at time zone 'Asia/Karachi');
You can change the time zone for a single session or for a single transaction with set session... or set local.... For example, this changes the time zone for the current session.
set session time zone 'Asia/Karachi';
Use the AT TIME ZONE construct:
SELECT EXTRACT(MONTH FROM login_timestamp AT TIME ZONE '-5');
-5 is the constant offset for Pakistan.
Details:
Ignoring timezones altogether in Rails and PostgreSQL
Try applying AT TIME ZONE. Demo
select extract(month from cast ('2017-07-01 01:00+03' as TIMESTAMP WITH TIME ZONE) AT TIME ZONE '+08') as monthNo
returns
monthno
1 6
I've a column like last_located_time which contain values like
2017-05-13T17:33:36.000+0000.
I have tried to remove only time, but no luck.
SELECT USERNAME, TO_DATE(SUBSTR(LAST_LOCATED_TIME,11,17),'HH:MI:SS') "lAST TIME"
FROM Tb_089
How should I extract only time value from the columns for all users?
Thanks in advance!
If you want the time component in the UTC time zone (so all times are being displayed in a common time zone) then:
(assuming you have a TIMESTAMP WITH TIME ZONE data type)
SELECT TO_CHAR(
last_located_time AT TIME ZONE 'UTC',
'HH24:MI:SS'
)
FROM Tb_089;
If you, instead, the column is an ISO 8601 formatted string:
SELECT TO_CHAR(
TO_TIMESTAMP_TZ(
last_located_time,
'YYYY-MM-DD"T"HH24:MI:SS.FFTZHTZM'
) AT TIME ZONE 'UTC',
'HH24:MI:SS'
)
FROM Tb_089;
If you want the time component as an interval:
SELECT CAST( utc_last_located_time AS TIMESTAMP ) - TRUNC( utc_last_located_time )
AS time_interval
FROM (
SELECT TO_TIMESTAMP_TZ(
last_located_time,
'YYYY-MM-DD"T"HH24:MI:SS.FFTZHTZM'
) AT TIME ZONE 'UTC' AS utc_last_located_time
FROM Tb_089
);
If you want the time component of the string (without adjusting for disparate time zones) then you could just do:
SELECT SUBSTR( last_located_time, 12, 8 )
FROM Tb_089
To_Date is used to convert Char and Varchar2 into Date.
You need to use To_Char which is opposite of To_Date
Select To_Char(LAST_LOCATED_TIME, 'HH24:MI:SS') "Last Time" from Tb_089;
How to get the date and time only up to minutes, not seconds, from timestamp in PostgreSQL. I need date as well as time.
For example:
2000-12-16 12:21:13-05
From this I need
2000-12-16 12:21 (no seconds and milliseconds only date and time in hours and minutes)
From a timestamp with time zone field, say update_time, how do I get date as well as time like above using PostgreSQL select query.
Please help me.
There are plenty of date-time functions available with postgresql:
See the list here
http://www.postgresql.org/docs/9.1/static/functions-datetime.html
e.g.
SELECT EXTRACT(DAY FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 16
For formatting you can use these:
http://www.postgresql.org/docs/9.1/static/functions-formatting.html
e.g.
select to_char(current_timestamp, 'YYYY-MM-DD HH24:MI') ...
To get the date from a timestamp (or timestamptz) a simple cast is fastest:
SELECT now()::date
You get the date according to your local time zone either way.
If you want text in a certain format, go with to_char() like #davek provided.
If you want to truncate (round down) the value of a timestamp to a unit of time, use date_trunc():
SELECT date_trunc('minute', now());
This should be enough:
select now()::date, now()::time
, pg_typeof(now()), pg_typeof(now()::date), pg_typeof(now()::time)