Apache Pig - DaysBetween()
This function accepts two date-time objects and calculates the number of days between the two given date-time objects.
Here is the syntax of the DaysBetween() function.
grunt> DaysBetween(datetime1, datetime2)
Assume that there is a file named 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.
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
And, we have loaded this file into Pig with a relation named doj_dob_data as shown below.
doj_dob_data = LOAD 'hdfs://localhost:9000/pig_data/doj_dob.txt' USING PigStorage(',') as (id:int, dob:chararray, doj:chararray);
Let us now 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'));
The above statement stores the result in the relation named daysbetween_data. Verify the contents of the relation using the Dump operator as shown below.
grunt> Dump daysbetween_data; (9243) (11372) (7981)