---
title: Query InfluxDB with Flux
description: Learn the basics of using Flux to query data from InfluxDB.
url: https://docs.influxdata.com/influxdb/cloud/query-data/get-started/query-influxdb/
estimated_tokens: 3258
product: InfluxDB Cloud (TSM)
version: cloud
---

# Query InfluxDB with Flux

This guide walks through the basics of using Flux to query data from InfluxDB. Every Flux query needs the following:

1. [A data source](#1-define-your-data-source)
2. [A time range](#2-specify-a-time-range)
3. [Data filters](#3-filter-your-data)

## 1\. Define your data source

Flux’s [`from()`](/flux/v0/stdlib/influxdata/influxdb/from/) function defines an InfluxDB data source. It requires a [`bucket`](/flux/v0/stdlib/influxdata/influxdb/from/#bucket) parameter. The following examples use `example-bucket` as the bucket name.

```js
from(bucket:"example-bucket")
```

## 2\. Specify a time range

Flux requires a time range when querying time series data. “Unbounded” queries are very resource-intensive and as a protective measure, Flux will not query the database without a specified range.

Use the [pipe-forward operator](/flux/v0/get-started/syntax-basics/#pipe-forward-operator) (`|>`) to pipe data from your data source into [`range()`](/flux/v0/stdlib/universe/range), which specifies a time range for your query. It accepts two parameters: `start` and `stop`. Start and stop values can be **relative** using negative [durations](/flux/v0/data-types/basic/duration/) or **absolute** using [timestamps](/flux/v0/data-types/basic/time/).

###### Example relative time ranges

```js
// Relative time range with start only. Stop defaults to now.
from(bucket:"example-bucket")
    |> range(start: -1h)

// Relative time range with start and stop
from(bucket:"example-bucket")
    |> range(start: -1h, stop: -10m)
```

Relative ranges are relative to “now.”

###### Example absolute time range

```js
from(bucket:"example-bucket")
    |> range(start: 2021-01-01T00:00:00Z, stop: 2021-01-01T12:00:00Z)
```

#### Use the following:

For this guide, use the relative time range, `-15m`, to limit query results to data from the last 15 minutes:

```js
from(bucket:"example-bucket")
    |> range(start: -15m)
```

## 3\. Filter your data

Pass your ranged data into `filter()` to narrow results based on data attributes or columns. `filter()` has one parameter, `fn`, which expects a [predicate function](/flux/v0/get-started/syntax-basics/#predicate-functions) evaluates rows by column values.

`filter()` iterates over every input row and structures row data as a Flux [record](/flux/v0/data-types/composite/record/). The record is passed into the predicate function as `r` where it is evaluated using [predicate expressions](/flux/v0/get-started/syntax-basics/#predicate-expressions).

Rows that evaluate to `false` are dropped from the output data. Rows that evaluate to `true` persist in the output data.

```js
// Pattern
(r) => (r.recordProperty comparisonOperator comparisonExpression)

// Example with single filter
(r) => (r._measurement == "cpu")

// Example with multiple filters
(r) => (r._measurement == "cpu" and r._field != "usage_system")
```

#### Use the following:

For this example, filter by the `cpu` measurement, `usage_system` field, and `cpu-total` tag value:

```js
from(bucket: "example-bucket")
    |> range(start: -15m)
    |> filter(fn: (r) => r._measurement == "cpu" and r._field == "usage_system" and r.cpu == "cpu-total")
```

## 4\. Yield your queried data

[`yield()`](/flux/v0/stdlib/universe/yield/) outputs the result of the query.

```js
from(bucket: "example-bucket")
    |> range(start: -15m)
    |> filter(fn: (r) => r._measurement == "cpu" and r._field == "usage_system" and r.cpu == "cpu-total")
    |> yield()
```

Flux automatically assumes a `yield()` function at the end of each script to output and visualize the data. Explicitly calling `yield()` is only necessary when including multiple queries in the same Flux query. Each set of returned data needs to be named using the `yield()` function.

## Congratulations!

You have now queried data from InfluxDB using Flux.

The query shown here is a basic example. Flux queries can be extended in many ways to form powerful scripts.

[Get started with Flux](/influxdb/cloud/query-data/get-started/) [Transform data with Flux](/influxdb/cloud/query-data/get-started/transform-data/)

#### Related

-   [Flux query basics](/flux/v0/get-started/query-basics/)
-   [Query data with Flux](/influxdb/cloud/query-data/flux/)
-   [from() function](/flux/v0/stdlib/influxdata/influxdb/from/)
-   [range() function](/flux/v0/stdlib/universe/range/)
-   [filter() function](/flux/v0/stdlib/universe/filter/)

[query](/influxdb/cloud/tags/query/) [flux](/influxdb/cloud/tags/flux/)