ES|QL MV_FIRST function
Elastic Cloud Serverless projects are autoscaled environments, fully managed by Elastic and available on Elastic Cloud. Availability This functionality is generally available and ready for production usage. Serverless interfaces and procedures might differ from classic Elastic Stack deployments. The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats. Availability 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.
Serverless
Generally available
Stack
Generally available
Returns the first value from a multi-value field.
field-
Expression that can be null, a single value, or multiple values.
Converts a multivalued expression into a single valued column containing the first value. This is most useful when reading from a function that emits multivalued columns in a known order like SPLIT.
The order that multivalued fields are read from
underlying storage is not guaranteed. It is frequently ascending, but don’t
rely on that. If you need the minimum value use MV_MIN instead of
MV_FIRST. MV_MIN has optimizations for sorted values so there isn’t a
performance benefit to MV_FIRST.
| field | result |
|---|---|
| boolean | boolean |
| cartesian_point | cartesian_point |
| cartesian_shape | cartesian_shape |
| date | date |
| date_nanos | date_nanos |
| date_range The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats. Availability Preview since 9.5 This functionality is in technical preview and is ready for evaluation. Use with caution in production; it is not recommended for mission-critical workloads. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features. Specific Support terms apply. 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. | date_range |
| double | double |
| double_range The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats. Availability Planned We plan to add this functionality in a future Elastic Stack update. Subject to changes. 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. | double_range |
| flattened The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats. Availability Preview since 9.5 This functionality is in technical preview and is ready for evaluation. Use with caution in production; it is not recommended for mission-critical workloads. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features. Specific Support terms apply. 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. | flattened |
| geo_point | geo_point |
| geo_shape | geo_shape |
| geohash | geohash |
| geohex | geohex |
| geotile | geotile |
| integer | integer |
| ip | ip |
| keyword | keyword |
| long | long |
| text | keyword |
| unsigned_long | unsigned_long |
| version | version |
ROW a="foo;bar;baz"
| EVAL first_a = MV_FIRST(SPLIT(a, ";"))
| a:keyword | first_a:keyword |
|---|---|
| foo;bar;baz | "foo" |