Type to search.

null_value

Serverless

Elastic Cloud Serverless projects are autoscaled environments, fully managed by Elastic and available on Elastic Cloud.

Availability

  • Generally available

    This functionality is generally available and ready for production usage.

Serverless interfaces and procedures might differ from classic Elastic Stack deployments.

Stack

The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats.

Availability

  • Generally available

    This functionality is generally available and ready for production usage.

Unless stated otherwise on the page, this functionality is available when your Elastic Stack is deployed on Elastic Cloud Hosted, Elastic Cloud Enterprise, Elastic Cloud on Kubernetes, and self-managed environments.

This documentation corresponds to the latest patch available for each minor version. If you're not using the latest patch, check the release notes for changes.

A null value cannot be indexed or searched. When a field is set to null, (or an empty array or an array of null values) it is treated as though that field has no values.

The null_value parameter allows you to replace explicit null values with the specified value so that it can be indexed and searched. For instance:

JSON 
PUT my-index-000001
{
  "mappings": {
    "properties": {
      "status_code": {
        "type":       "keyword",
        "null_value": "NULL"
      }
    }
  }
}
PUT my-index-000001/_doc/1
{
  "status_code": null
}
PUT my-index-000001/_doc/2
{
  "status_code": []
}
GET my-index-000001/_search
{
  "query": {
    "term": {
      "status_code": "NULL"
    }
  }
}
  1. Replace explicit null values with the term NULL.
  2. An empty array does not contain an explicit null, and so won’t be replaced with the null_value.
  3. A query for NULL returns document 1, but not document 2.
Important

The null_value needs to be the same data type as the field. For instance, a long field cannot have a string null_value.

Note

The null_value only influences how data is indexed, it doesn’t modify the _source document.