# Aggregation help

**URL:** <https://discuss.elastic.co/t/aggregation-help/183622>\
**Category:** Logstash\
**Created:** [May 30, 2019, 10:24pm UTC](https://discuss.elastic.co/t/aggregation-help/183622 "2019-05-30T22:24:11Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![grazer](https://avatars.discourse-cdn.com/v4/letter/g/e9bcb4/32.png) [@grazer](https://discuss.elastic.co/u/grazer)\
**Post date:** [May 30, 2019, 10:24pm UTC](https://discuss.elastic.co/t/aggregation-help/183622/1 "2019-05-30T22:24:11Z")

</div>

the input file has so many date stamps, I want to aggregate on month or year. when I create the index and I start to define it I only get the @timestamp option which is the date the csv file was imported I want to be able to aggregate on lastmodifcationtime...

```
		}
	separator => ","
	columns => ["publicfoldername","subject","creationtime","lastmodificationtime","hasattachments","itemtype","messagesize","servername","databasename","originatingserver"]
	  }
  date {
	match => ["lastmodificationtime", "dd-MM-yyyy HH:mm:ss"]
	**target => "lastmodificationtime"**
		}
```

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [June 27, 2019, 10:24pm UTC](https://discuss.elastic.co/t/aggregation-help/183622/2 "2019-06-27T22:24:15Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.