# ElasticSearch aggregate on a scripted nested field

**URL:** <https://discuss.elastic.co/t/elasticsearch-aggregate-on-a-scripted-nested-field/298841>\
**Category:** Elasticsearch\
**Tags:** runtime-fields\
**Created:** [March 4, 2022, 11:23am UTC](https://discuss.elastic.co/t/elasticsearch-aggregate-on-a-scripted-nested-field/298841 "2022-03-04T11:23:15Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![doogyatnesta](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/doogyatnesta/32/98588_2.png) [@doogyatnesta](https://discuss.elastic.co/u/doogyatnesta)\
**Post date:** [March 4, 2022, 5:16pm UTC](https://discuss.elastic.co/t/elasticsearch-aggregate-on-a-scripted-nested-field/298841/2 "2022-03-04T17:16:49Z")

</div>

I've managed to figure this out in the end.

The two things I hadn't realised were:

1. You can provide a `script` instead of a `field` key to bucket aggregations.
2. Instead of using `nested` queries, you can access nested values directly using `params._source`.

The combination of these two things allowed me to write the correct query:

```json
{
  "size": 0,
  "aggs": {
    "max.float_property": {
      "terms": {
        "script": "double max = 0; for (item in params._source.entities) { if (item.float_property > max) { max = item.float_property; }} return max;"
      }
    }
  }
}

```

Response:

```json
{
  ...
  "aggregations": {
    "max.float_property": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": "0.9",
          "doc_count": 2
        },
        {
          "key": "0.6",
          "doc_count": 1
        }
      ]
    }
  }
}

```

I'm confused though, because I thought the correct way to access `nested` fields was by using the `nested` query type. Unfortunately there's very little documentation for this, so I'm still unsure if this is the intended/correct way to aggregate on scripted nested fields.

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_[View the full topic](https://discuss.elastic.co/t/elasticsearch-aggregate-on-a-scripted-nested-field/298841)._