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What is SubtractDuration() function in Apache Pig ?
- The SubtractDuration() function accepts a date-time object and a duration objects, and subtract the given duration to the date-time object and returns a new date-time object.
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Syntax
grunt> SubtractDuration(datetime, duration)
Example
- Ensure that we have a file named wikitechy_date.txt in the HDFS directory /pig_data/.
- This file contains the date-of-birth details of a particular person, it has person id, date and time and some duration according to ISO 8601 standard.
wikitechy_date.txt
001,1989/09/26 09:00:00,PT1M
002,1980/06/20 10:22:00,P1Y
003,1990/12/19 03:11:44,P3M
- We have loaded this file into Pig with a relation named date_duration as given below.
grunt> date_duration = LOAD 'hdfs://localhost:9000/pig_data/wikitechy_date.txt' USING PigStorage(',')
as (id:int, date:chararray, duration:chararray)
- We have loaded this file into Pig with a relation named date_duration as given below.
- Following is an example of the SubtractDuration() function.
- Now you can subtract certain duration from the given date-time object using this method as given below.
subtractduration_data = foreach date_duration generate(date,duration),
SubtractDuration(ToDate(date,'yyyy/MM/dd HH:mm:ss'), duration);
Verification
- Verify the content of this relation using the Dump operator as given below.
grunt> Dump subtractduration_data;
Output
- The result of the statement will be stored in the relation named subtractduration_data.
((1989/09/26 09:00:00,PT1M),1989-09-26 T08:59:00.000+05:30)
((1980/06/20 10:22:00,P1Y),1979-06-20 T10:22:00.000+05:30)
((1990/12/19 03:11:44,P3M),1990-09-19 T03:11:44.000+05:30)