﻿---
title: Bucket selector aggregation
description: A parent pipeline aggregation which executes a script which determines whether the current bucket will be retained in the parent multi-bucket aggregation...
url: https://www.elastic.co/elastic/docs-builder/docs/2970/reference/aggregations/search-aggregations-pipeline-bucket-selector-aggregation
products:
  - Elasticsearch
---

# Bucket selector aggregation
A parent pipeline aggregation which executes a script which determines whether the current bucket will be retained in the parent multi-bucket aggregation. The specified metric must be numeric and the script must return a boolean value. If the script language is `expression` then a numeric return value is permitted. In this case 0.0 will be evaluated as `false` and all other values will evaluate to true.
<note>
  The bucket_selector aggregation, like all pipeline aggregations, executes after all other sibling aggregations. This means that using the bucket_selector aggregation to filter the returned buckets in the response does not save on execution time running the aggregations.
</note>


## Syntax

A `bucket_selector` aggregation looks like this in isolation:
```js
{
  "bucket_selector": {
    "buckets_path": {
      "my_var1": "the_sum",                     
      "my_var2": "the_value_count"
    },
    "script": "params.my_var1 > params.my_var2"
  }
}
```



| Parameter Name | Description                                                                                                                                                                                                                           | Required | Default Value |
|----------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------|---------------|
| `script`       | The script to run for this aggregation. The script can be inline, file or indexed. (see [Scripting](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/2970/explore-analyze/scripting)for more details)                    | Required |               |
| `buckets_path` | A map of script variables and their associated path to the buckets we wish to use for the variable(see [`buckets_path` Syntax](/elastic/docs-builder/docs/2970/reference/aggregations/pipeline#buckets-path-syntax) for more details) | Required |               |
| `gap_policy`   | The policy to apply when gaps are found in the data (see [Dealing with gaps in the data](/elastic/docs-builder/docs/2970/reference/aggregations/pipeline#gap-policy) for more details)                                                | Optional | `skip`        |

The following snippet only retains buckets where the total sales for the month is more than 200:
```json

{
  "size": 0,
  "aggs": {
    "sales_per_month": {
      "date_histogram": {
        "field": "date",
        "calendar_interval": "month"
      },
      "aggs": {
        "total_sales": {
          "sum": {
            "field": "price"
          }
        },
        "sales_bucket_filter": {
          "bucket_selector": {
            "buckets_path": {
              "totalSales": "total_sales"
            },
            "script": "params.totalSales > 200"
          }
        }
      }
    }
  }
}
```

And the following may be the response:
```json
{
   "took": 11,
   "timed_out": false,
   "_shards": ...,
   "hits": ...,
   "aggregations": {
      "sales_per_month": {
         "buckets": [
            {
               "key_as_string": "2015/01/01 00:00:00",
               "key": 1420070400000,
               "doc_count": 3,
               "total_sales": {
                   "value": 550.0
               }
            },<1>
            {
               "key_as_string": "2015/03/01 00:00:00",
               "key": 1425168000000,
               "doc_count": 2,
               "total_sales": {
                   "value": 375.0
               }
            }
         ]
      }
   }
}
```

1. Bucket for `2015/02/01 00:00:00` has been removed as its total sales was less than 200