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Questions tagged [date-arithmetic]

The term 'date-arithmetic' refers to determining via code such information as how many days, hours, etc. between two calendar dates, and determining the last day of the month, or whether a date is a weekday or a weekend. Be sure to also include the appropriate programming or database tag.

Many computer languages provide for date arithmetic, including , , and languages. Most languages store data with a type of date internally as a number of days since a certain date, such as January 1st 1970 for Unix.

Typical Considerations

  • Basic calculations such as number of days between two dates, number of months between two dates, etc.
  • Scheduling problems often involve how to determine the fifth business day of the month, the last day of the month, the fourth Thursday of the month
  • Regional or Client-specific concerns include whether certain days are holidays, etc.
  • Week number of the year (ISO: Monday as first day of week, Unix: Sunday as first day of week)
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How do I get a timestamp in JavaScript?

I want a single number that represents the current date and time, like a Unix timestamp.
Pablo Fernandez
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How do I find the time difference between two datetime objects in python?

How do I tell the time difference in minutes between two datetime objects?
Hobhouse
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Calculating days between two dates with Java

I want a Java program that calculates days between two dates. Type the first date (German notation; with whitespaces: "dd mm yyyy") Type the second date. The program should calculates the number of days between the two dates. How can I include…
user3025448
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How can I do time/hours arithmetic in Google Spreadsheet?

How do I do time/hour arithmetic in a Google spreadsheet? I have a value that is time (e.g., 36:00:00) and I want to divide it by another time (e.g., 3:00:00) and get 12. If I divide just one by the other, I get 288:00:00 when what I want is 12 (or…
user128807
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How to find the duration of difference between two dates in java?

I have two objects of DateTime, which need to find the duration of their difference, I have the following code but not sure how to continue it to get to the expected results as following: Example: 11/03/14 09:30:58 11/03/14 09:33:43 …
J888
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How to get difference between two dates in months using MySQL query?

I'm looking to calculate the number of months between 2 date time fields. Is there a better way than getting the Unix timestamp and then dividing by 2 592 000 (seconds) and rounding up within MySQL?
Darryl Hein
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Oracle DateTime in Where Clause?

I have sql something like this: SELECT EMP_NAME, DEPT FROM EMPLOYEE WHERE TIME_CREATED >= TO_DATE('26/JAN/2011','dd/mon/yyyy') -> This returns 10 rows and TIME_CREATED = '26-JAN-2011' Now when i do this i don't get any rows back, SELECT EMP_NAME,…
sanjeev40084
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Calculate difference between 2 date / times in Oracle SQL

I have a table as follows: Filename - varchar Creation Date - Date format dd/mm/yyyy hh24:mi:ss Oldest cdr date - Date format dd/mm/yyyy hh24:mi:ss How can I calcuate the difference in hours minutes and seconds (and possibly days) between the two…
Steve
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Check if year is leap year in javascript

function leapYear(year){ var result; year = parseInt(document.getElementById("isYear").value); if (years/400){ result = true } else if(years/100){ result = false } else if(years/4){ result= true } …
BigBob
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Delete rows with date older than 30 days with SQL Server query

I need a SQL statement to delete row that are older than 30 days. My table events has a field date that contains the date and the time it was inserted in the database. Will this work? SELECT * from Results WHERE [Date] >= DATEADD(d, -30, getdate())
Alex
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MySQL how to fill missing dates in range?

I have a table with 2 columns, date and score. It has at most 30 entries, for each of the last 30 days one. date score ----------------- 1.8.2010 19 2.8.2010 21 4.8.2010 14 7.8.2010 10 10.8.2010 14 My problem is that some dates are…
Jerry2
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How do you find results that occurred in the past week?

I have a books table with a returned_date column. I'd like to see the results for all of the books with a returned date that occurred in the past week. Any thoughts? I tried doing some date math, but Postgres wasn't happy with my attempt.
Huuuze
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How to change the default time zone in R?

How can I change the default timezone in R? I'm working with time series. All my time series are defined in UTC time zone, but if I print a date it is always done in CET/CEST time zone.
Paul PUGET
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Add a month to a Date

I am trying to add a month to a date i have. But then its not possible in a straight manner so far. Following is what i tried. d <- as.Date("2004-01-31") d + 60 # [1] "2004-03-31" Adding wont help as the month wont be…
Vineeth Mohan
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MySQL Select last 7 days

I read some posts here and seems like nothing special but I can not still select the entries of the last days. SELECT p1.kArtikel, p1.cName, p1.cKurzBeschreibung, p1.dLetzteAktualisierung, p1.dErstellt, p1.cSeo, …
karadayi
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