# Is sum(null)=0 is good specification? in timelion

**URL:** <https://discuss.elastic.co/t/is-sum-null-0-is-good-specification-in-timelion/201118>\
**Category:** Kibana\
**Tags:** timelion\
**Created:** [September 26, 2019, 12:03am UTC](https://discuss.elastic.co/t/is-sum-null-0-is-good-specification-in-timelion/201118 "2019-09-26T00:03:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![alfyukio](https://avatars.discourse-cdn.com/v4/letter/a/b5a626/32.png) [@alfyukio](https://discuss.elastic.co/u/alfyukio)\
**Post date:** [September 26, 2019, 12:03am UTC](https://discuss.elastic.co/t/is-sum-null-0-is-good-specification-in-timelion/201118/1 "2019-09-26T00:03:14Z")

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Hi,

I found an issue in sum of NULL in timelion.  
avg:NULLVALUE =NULL  
max:NULLVALUE = NULL  
but  
sum:NULLVALUE = 0

Is it good specification? I was trying to make out NULL or 0, but unable to do it using sum.

Thanks in advance.

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**Author:** ![mikecote](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mikecote/32/58549_2.png) [@mikecote](https://discuss.elastic.co/u/mikecote)\
**Post date:** [September 26, 2019, 4:59pm UTC](https://discuss.elastic.co/t/is-sum-null-0-is-good-specification-in-timelion/201118/2 "2019-09-26T16:59:27Z")

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Hi @alfyukio,

Yes sum of null returning 0 is expected behaviour by design. The sum of an empty set is well defined (0) while the average and max aren't when you have no data.

You can see a similar discussion here: [https://github.com/elastic/elasticsearch/issues/31887](https://github.com/elastic/elasticsearch/issues/31887).

Mike.

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<div class="post-metadata">

**Author:** ![alfyukio](https://avatars.discourse-cdn.com/v4/letter/a/b5a626/32.png) [@alfyukio](https://discuss.elastic.co/u/alfyukio)\
**Post date:** [September 26, 2019, 11:36pm UTC](https://discuss.elastic.co/t/is-sum-null-0-is-good-specification-in-timelion/201118/3 "2019-09-26T23:36:50Z")

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Hi @mikecote,

Thanks. I should have looked at the issue:31887.  
If it is by design. OK.

Yukio

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [October 24, 2019, 11:36pm UTC](https://discuss.elastic.co/t/is-sum-null-0-is-good-specification-in-timelion/201118/4 "2019-10-24T23:36:50Z")

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