---
title: schema.measurementFieldKeys() function
description: schema.measurementFieldKeys() returns a list of fields in a measurement.
url: https://docs.influxdata.com/flux/v0/stdlib/influxdata/influxdb/schema/measurementfieldkeys/
estimated_tokens: 968
product: Flux
version: v0
---

# schema.measurementFieldKeys() function

-   Flux 0.88.0+
-   View InfluxDB support

`schema.measurementFieldKeys()` returns a list of fields in a measurement.

Results include a single table with a single column, `_value`.

##### Function type signature

```js
(bucket: string, measurement: A, ?start: B, ?stop: C) => stream[D] where A: Equatable, D: Record
```

For more information, see [Function type signatures](/flux/v0/function-type-signatures/).

## Parameters

### bucket

(Required) Bucket to retrieve field keys from.

### measurement

(Required) Measurement to list field keys from.

### start

Oldest time to include in results. Default is `-30d`.

### stop

Newest time include in results. The stop time is exclusive, meaning values with a time equal to stop time are excluded from the results. Default is `now()`.

Relative start times are defined using negative durations. Negative durations are relative to `now()`. Absolute start times are defined using time values.

## Examples

### Query field keys from an InfluxDB measurement

```js
import "influxdata/influxdb/schema"

schema.measurementFieldKeys(bucket: "example-bucket", measurement: "example-measurement")
```

#### Not supported in the Flux REPL

`schema` functions can retrieve schema information when executed within the context of InfluxDB, but not from the [Flux REPL](/influxdb/cloud/tools/repl/).

#### Related

-   [Explore your data schema with Flux](/influxdb/v2/query-data/flux/explore-schema/)
-   [SHOW FIELD KEYS in InfluxQL](/influxdb/v1/query_language/explore-schema#show-field-keys)

[metadata](/flux/v0/tags/metadata/)