Is there a way to have the time (HH:mm) between two timestamps in postgresql ?
The difference between two timestamps can be calculated using -, e.g.:
timestamp_one - timestamp_two
However, the result is not a "time", but an "interval".
You can display that in the form HH:mm using to_char():
to_char(timestamp_one - timestamp_two, 'HH:mi')
but what do you expect for differences larger then 24 hours?
Related
I have to calculate the number of days between two dates and I search and I don't find any similar function available in ADF.
what I've noticed so far is that if I want to get the number of days between 2 columns, it means that the columns must be date columns, but I have timestamp columns (date + time)
how can I transform these columns into Date columns? or do you have other idea?
Using the fact that 86,400 is the number of seconds in a day
Now, using the function
ticks,
it returns the ticks property value for a specified timestamp. A tick
is a 100-nanosecond interval.
#string(div(sub(ticks(last_date),ticks(first_date)),864000000000))
Can re-format any type timestamp using function formatDateTime()
#formatDateTime(your_time_stamp,'yyyy-MM-dd HH:mm:ss')
Example:
#string(div(sub(ticks('2022-02-23 15:58:16'),ticks('2022-01-31 15:58:16')),864000000000))
This is the expression that I used for Data Flow.
toDate(toString({max_po create date},'yyyy-MM-dd')) - toDate(toString(max_datetimetoday,'yyyy-MM-dd'))
max_po, create date and max_datetimetoday are TimeStamp(date + time) columns.
The result is in days.
My database table has the timestamp format "2019-12-08T13:03:16.502639-0600". I am having difficult figuring out how to filter a 24 hour range of dates so I only get the data plucked from inside that 24 hour running period of time. I need something like now() then back 24 hours on a running basis. I have tried several ways but none of them work.
Do I need to parse the timestamp first and only use the parts I need?
In Python, the query could look like this:
r.table('MyDB').filter(r.row['timestamp'] > r.now() - 24*60*60).run(con)
Calculate the time between these two timestamps in PostgreSQL, create_time='2017-11-02 05:51:13' and update_time='2017-11-02 07:36:18' and display it on HH:MM:SS Format. it should display like this 01:45:04
You can try just subtracting the two timestamps, then using to_char to extract out the time portion:
select
SELECT to_char('2017-11-02 07:36:18'::timestamp -
'2017-11-02 05:51:10'::timestamp, 'HH:MI:SS');
Output:
to_char
01:45:08
Demo
I'm interested in knowing the different possibilities to operate with datetimes in SQLite and understand its pros and cons. I did not find anywhere a detailed explanation of all the alternatives.
So far I have learned that
SQLite doesn't actually have a native storage class for timestamps /
dates. It stores these values as NUMERIC or TEXT typed values
depending on input format. Date manipulation is done using the builtin
date/time functions, which know how to convert inputs from the other
formats.
(quoted from here)
When any operation between datetimes is needed, I have seen two different approaches:
julianday function
SELECT julianday(OneDatetime) - julianday(AnotherDatetime) FROM MyTable;
Number of days is returned, but this can be fractional.
Therefore, you can also get some other measures of time with some extra operations. For instance, to get minutes:
SELECT CAST ((
julianday(OneDatetime) - julianday(AnotherDatetime)
) * 24 * 60 AS INTEGER)
Apparently julianday could cause some problems:
Bear in mind that julianday returns the (fractional) number of 'days'
- i.e. 24hour periods, since noon UTC on the origin date. That's usually not what you need, unless you happen to live 12 hours west of
Greenwich. E.g. if you live in London, this morning is on the same
julianday as yesterday afternoon.
More information in this post.
strftime function
SELECT strftime("%s", OneDatetime)-strftime("%s", AnotherDatetime) FROM MyTable;
Number of seconds is returned. Similarly, you can also get some other measures of time with some extra operations. For instance, to get minutes:
SELECT (strftime("%s", OneDatetime)-strftime("%s", AnotherDatetime))/60 FROM MyTable;
More information here.
My conclusion so far is: julianday seems easier to use, but can cause some problems. strftime seems more verbose, but also safer. Both of them provide only as results a single unit (either days or hours or minutes or seconds), but not a combination of many.
Question
1) Is there any other possibility to operate with datetimes?
2) What would be the best way to get directly the difference of two datetimes in time format (or date or datetime), where datetime would be formatted as 'YYYY-mm-dd HH:MM:SS', and the result would be something in the same format?
I would have imagined that something like the following would work, but it does not:
SELECT DATETIME('2016-11-04 08:05:00') - DATETIME('2016-11-04 07:00:00') FROM MyTable;
> 01:05:00
Julian day numbers are perfectly safe when computing differences.
The only problem would be if you tried to convert them into a date by truncating any fractional digits; this would result in noon, not midnight. (The same could happen if you tried to store them in integer variables.) But that is not what you're doing here.
SQLite has no built-in function to compute date/time differences; you have to convert date/time values into some number first. Whether you use (Julian) days or seconds does not really matter from a technical point of view; use whatever is easier in your program.
If you started with a different format, you might want to convert the resulting difference back into that format, e.g.:
time(difference_value, 'unixepoch') -- from seconds to hh:mm:ss
time(0.5 + difference_value) -- from Julian days to hh:mm:ss
I am converting an Unix script with a SQL transact command to a PostgreSQL command.
I have a table with records that have a field last_update_time(xtime) and I want to select every record in the table that has been updated within a selected period.
Say, the current time it 05/01/2012 10:00:00 and the selected time is 04/01/2012 23:55:00. How do I select all the records from a table that have been updated between these dates. I have converted the 2 times to seconds in the Unix script prior to issuing the psql command, and have calculated the interval in seconds between the 2 periods.
I thought something like
SELECT A,B,C FROM table
WHERE xtime BETWEEN now() - interval '$selectedtimeParm(in secs)' AND now();
I am having trouble evaluating the Parm for the selectedtimeParm - it doesn't resolve properly.
Editor's note: I did not change the inaccurate use of the terms period, time frame, time and date for the datetime type timestamp because I discuss that in my answer.
What's wrong with:
SELECT a,b,c
FROM table
WHERE xtime BETWEEN '2012-04-01 23:55:00'::timestamp
AND now()::timestamp;
If you want to operate with a count of seconds as interval:
...
WHERE xtime BETWEEN now()::timestamp - (interval '1s') * $selectedtimeParm
AND now()::timestamp;
Note the standard ISO 8601 date format YYYY-MM-DD h24:mi:ss which is unambiguous with any locale or DateStyle setting.
The first value for the BETWEEN construct must be the smaller one. If you don't know which value is smaller use BETWEEN SYMMETRIC instead.
In your question you refer to the datetime type timestamp as "date", "time" and "period". In the title you used the term "time frames", which I changed to "timestamps". All of these terms are wrong. Freely interchanging them makes the question even harder to understand.
That, and the fact that you only tagged the question psql (the problem hardly concerns the command line terminal) might help to explain why nobody answered for days. Normally, it's a matter of minutes around here. I had a hard time understanding your question.
Understand the data types date, interval, time and timestamp - with or without time zone. Start by reading the chapter "Date/Time Types" in the manual.
Error message would have gone a long way, too.
For anyone who is looking for the fix to this. You need to remove timestamp from the where clause and use BETWEEN!
TABLENAME.COL-NAME-FOR-TIMESTAMP BETWEEN '2020-01-29 04:18:00-06' AND CURRENT_TIMESTAMP