Hi Steve , Thanks for the suggestion it worked . Below is the modified script .
A = FOREACH (COGROUP OUTER) group as url , (1-$d)+$d*(SUM(a.values) IS NULL ? 0.0 : SUM(a.values)) as totalValue How can I change it so that SUM function can be avoided twice . I am new to the PIG scripting and so I couldn't come up with better ways . Thanks, Akoppula -----Original Message----- From: Steve Bernstein [mailto:steve.bernst...@deem.com] Sent: Monday, April 14, 2014 7:55 PM To: user@pig.apache.org Subject: RE: Extending Pig SUM function How about re-projecting with: ( sumValue IS NULL ? 0.0 : sumValue) AS sumValue You may want to cast sumValue to avoid cast warnings. -----Original Message----- From: Koppula, Abhilash Reddy [mailto:akopp...@indiana.edu] Sent: Monday, April 14, 2014 4:44 PM To: user@pig.apache.org Subject: Extending Pig SUM function Hi All, The built in Pig SUM eval function returns null if the bag is empty . How can I override this(as simple as possible ) to return 0 instead of null . public class CustomSum extends SUM{ // Which methods to override. } Or Is there any way I can do it in script to check if SUM returned null then make it 0. Eg : A = FOREACH (COGROUP OUTER) group as url , (1-$d)+$d*SUM(a.values) as totalValue . I am doing a outer COGROUP . So there are some records in the group which doesn't have values and in that case I would like to return constant(1-$d) . However as SUM returns null , totalValues is becoming null. Thanks, Abhilash
