date-arithmetic | 易学教程

Calculate Date/Time Difference in Java considering AM/PM

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问题 I want to calculate the difference between two date/time in java using Date and Calendar classes. The format that I have is "2012-01-24 12:30:00 PM". I have implemented my own method and also google it to work with others, but haven't getting the right hint to handle AM and PM values. The date/time difference got troubled whenever the time have 12(AM/PM) in it. For example if I have date/time "2012-01-24 12:30:00 PM" and "2012-01-24 02:30:00 PM" it shows the difference is 10 hours.

Date comparison returns unusual result - SQL Oracle

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I have a table of the structure: +---------+--------------+-----------------+---------------+-------+------+ | week_no | long_week_no | week_start_date | week_end_date | month | year | +---------+--------------+-----------------+---------------+-------+------+ | 1 | 1A | 01/01/2015 | 03/01/2015 | JAN | 2015 | | 1 | 1B | 04/01/2015 | 10/01/2015 | JAN | 2015 | | 2 | 2 | 11/01/2015 | 17/01/2015 | JAN | 2015 | | 3 | 3 | 18/01/2015 | 24/01/2015 | JAN | 2015 | | .. | .. | .. | .. | .. | .. | | 51 | 51 | 14/12/2014 | 20/12/2015 | DEC | 2014 | +---------+--------------+-----------------+--------------

How to calculate an age based on a birthday? [duplicate]

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问题 Possible Duplicate: How do I calculate someone’s age in C#? I want to write an ASP.NET helper method which returns the age of a person given his or her birthday. I've tried code like this: public static string Age(this HtmlHelper helper, DateTime birthday) { return (DateTime.Now - birthday); //?? } But it's not working. What is the correct way to calculate the person's age based on their birthday? 回答1: Stackoverflow uses such function to determine the age of a user. Calculate age in C# The

MySQL Select last 7 days

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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, p2.kartikelpict, p2.nNr, p2.cPfad FROM tartikel AS p1 WHERE DATE(dErstellt) > (NOW() - INTERVAL 7 DAY) INNER JOIN tartikelpict AS p2 ON (p1.kArtikel = p2.kArtikel) WHERE (p2.nNr = 1) ORDER BY p1.kArtikel DESC LIMIT 100;', $connection); If I add the between today and last 7 days my Code will not output anything. The WHERE clause is misplaced, it has to follow the table references and

Oracle Date - How to add years to date

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I have a date field DATE = 10/10/2010 sum = 4 (this are number of years by calculation) is there a way to add four years to 10/10/2010 and make it 10/10/2014? Try adding months (12 * number of years) instead. Like this- add_months(date'2010-10-10', 48) Use add_months Example: SELECT add_months( to_date('10-OCT-2010'), 48 ) FROM DUAL; Warning add_months, returns the last day of the resulting month if you input the last day of a month to begin with. So add_months(to_date('28-feb-2011'),12) will return 29-feb-2012 as a result. I believe you could use the ADD_MONTHS() function. 4 years is 48

Add 2 months to current timestamp

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问题 How can I add months to a timestamp value in Oracle? In my query, it's getting converted to date value instead: SELECT add_months(current_timestamp,2) FROM dual; The actual output is: ADD_MONTH 11-MAR-13 The expected output is: 2013-01-01 00:00:00.000000000+00:00 回答1: This will give you the date and the time as a TIMESTAMP data type: select TO_TIMESTAMP(TO_CHAR(ADD_MONTHS(SYSDATE, 2), 'YYYYMMDD HH24:MI'), 'YYYYMMDD HH24:MI') from dual; If you need more or less precision (E.G. rounding) than

Find the NSDate for next Monday [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I want to get the date of the next Monday after the current date. So if today's date is 2013-08-09 (Friday) then I want to get the date 2013-08-12. How can I do this? 回答1: This piece of code should get what you want. It simply calculates how many days are from monday and append it from current's date. NSDate

How to subtract years?

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I have a date in R, e.g.: dt = as.Date('2010/03/17') I would like to subtract 2 years from this date, without worrying about leap years and such issues, getting as.Date('2010-03-17') . How would I do that? Shane The easiest thing to do is to convert it into POSIXlt and subtract 2 from the years slot. > d <- as.POSIXlt(as.Date('2010/03/17')) > d$year <- d$year-2 > as.Date(d) [1] "2008-03-17" See this related question: How to subtract days in R? . With lubridate library(lubridate) ymd("2010/03/17") - years(2) You could use seq : R> dt = as.Date('2010/03/17') R> seq(dt, length=2, by="-2 years")[2

How to get a list of months between 2 given dates using a query?

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问题 I have 2 dates, say 28-Mar-2011 and 29-Jun-2011. I need an sql query that will display the months between these 2 dates including the months containing the dates, ie. June, May, April and March. 回答1: Something like this SQL> ed Wrote file afiedt.buf select to_char( add_months( start_date, level-1 ), 'fmMonth' ) from (select date '2011-03-30' start_date, date '2011-06-29' end_date from dual) connect by level <= months_between( trunc(end_date,'MM'), trunc(start_date,'MM') ) * + 1 SQL> / TO_CHAR

Oracle: how to add minutes to a timestamp?

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I need to add 30 minutes to values in a Oracle date column. I do this in my SELECT statement by specifying to_char(date_and_time + (.000694 * 31) which works fine most of the time. But not when the time is on the AM/PM border. For example, adding 30 minutes to 12:30 [which is PM] returns 1:00 which is AM. The answer I expect is 13:00 . What's the correct way to do this? All of the other answers are basically right but I don't think anyone's directly answered your original question. Assuming that "date_and_time" in your example is a column with type DATE or TIMESTAMP, I think you just need to