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What is DaysBetween() Function?
- The DaysBetween function subtracts the FromDate from the ToDate, returning the number whole day difference.
- The time value of each date is taken account of - only whole 24 hour chunks are counted as whole days.
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DaysBetween() function in Apache Pig
- This function accepts two date-time objects and calculates the number of days between the two given date-time objects.
Syntax
grunt> DaysBetween(datetime1, datetime2)
Example
- Ensure that we have a file named wikitechy_doj_dob.txt in the HDFS directory /pig_data/.
- This file contains the date-of-birth and date-of-joining details of a particular person, id, dateof-birth, and date-of-join as given below.
wikitechy_doj_dob.txt
001,26/09/1989 09:00:00,16/01/2015 09:00:00
002,20/06/1980 10:22:00,10/08/2011 09:00:00
003,19/12/1990 03:11:44,25/10/2012 09:00:00
- We have loaded this file into Pig with a relation named doj_dob_data as given below.
doj_dob_data = LOAD 'hdfs://localhost:9000/pig_data/wikitechy_doj_dob.txt' USING PigStorage(',')
as (id:int, dob:chararray, doj:chararray);
- Now you can calculate the number of days between date-of-birth and date-of-join of the employees using the DaysBetween() function.
grunt> daysbetween_data = foreach doj_dob_data generate DaysBetween(ToDate(doj,'dd/MM/yyyy HH:mm:ss'),
ToDate(dob,'dd/MM/yyyy HH:mm:ss'));
Verification
Verify the contents of the relation using the Dump operator as given below.
grunt> Dump daysbetween_data;
Output
- The above statement stores the result in the relation named daysbetween_data.
(9243)
(11372)
(7981)