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What is GetDay(datetime)function in Apache Pig ?
- The GetDay(datetime) function will accept a date-time object as a parameter and return the current day of the given date-time object.
- The GetDay() method returns the day of the week for the specified date which is given in GetDay() method.
- The GetDay() gets the day of the month which is represented by this instance.
Syntax
grunt> GetDay(datetime)
Example
- Ensure that we have a file named wikitechy_date.txt in the HDFS directory /pig_data/ as given below.
- This file contains the date-of-birth details of a particular person, id, date, and time.
wikitecht_date.txt
111,1990/09/26 09:00:00
112,1981/06/20 10:22:00
113,1991/12/19 03:11:44
- We have loaded this file into Pig with a relation named date_data as given below.
grunt> date_data = LOAD 'hdfs://localhost:9000/pig_data/wikitechy_date.txt' USING PigStorage(',')
as (id:int,date:chararray);
- Following is an example of the GetDay() function.
- The GetDay() function will retrive the day from the given Date-Time object. So, first of all, let us calculate the date-time objects of all employees using todate() function as shown below.
grunt> todate_data = foreach date_data generate ToDate(date,'yyyy/MM/dd HH:mm:ss')
as (date_time:DateTime );
grunt> Dump todate_data;
(1990-09-26T09:00:00.000+05:30)
(1981-06-20T10:22:00.000+05:30)
(1991-12-19T03:11:44.000+05:30)
- Now, get the day from the date-of-birth using GetDay() function and store it in the relation named getday_data.
grunt> getday_data = foreach todate_data generate(date_time), GetDay(date_time);
Verification
- Verify the contents of the getday_data relation using the Dump operator.
grunt> Dump getday_data;
Output
(1990-09-26T09:00:00.000+05:30,26)
(1981-06-20T10:22:00.000+05:30,20)
(1991-12-19T03:11:44.000+05:30,19)