# Date Histogram when only have start and end dates (or duration)?

**URL:** <https://discuss.elastic.co/t/date-histogram-when-only-have-start-and-end-dates-or-duration/34726>\
**Category:** Elasticsearch\
**Created:** [November 16, 2015, 8:07pm UTC](https://discuss.elastic.co/t/date-histogram-when-only-have-start-and-end-dates-or-duration/34726 "2015-11-16T20:07:40Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![colings86](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/colings86/32/44960_2.png) [@colings86](https://discuss.elastic.co/u/colings86)\
**Post date:** [November 17, 2015, 9:42am UTC](https://discuss.elastic.co/t/date-histogram-when-only-have-start-and-end-dates-or-duration/34726/2 "2015-11-17T09:42:11Z")

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You might find the following link helpful for this. It is a very similar use-case:

> [@Display concurrency in data on Kibana](https://discuss.elastic.co/t/display-concurrency-in-data-on-kibana/26006):
>
> I have fields with start date and duration (seconds) representing start and duration of a phone call. I would like to define concurrency (a number) when the same destination (also a field) is active within the same duration. That is if a ncall starts now for 30 seconds and another call to the same destination starts 15 seconds into the first call, concurrency should be 2 for the remaining 15 seconds. How do I define this in Kibana visualization as a line graph over time?

Specifically this post in the topic, but I recommend reading the whole topic to get context: [Display concurrency in data on Kibana - #3 by colings86](https://discuss.elastic.co/t/display-concurrency-in-data-on-kibana/26006/3)

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