added flux getting started docs

content/v2.0/query-data/_index.md

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+---
+title: Query data in InfluxDB
+seotitle: Query data stored in InfluxDB
+description: placeholder
+menu:
+  v2_0:
+    name: Query data
+    weight: 2
+---
+
+_Placeholder content for the query data page._

content/v2.0/query-data/flux/_index.md

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+---
+title: Introduction to Flux
+description: >
+  Flux is InfluxData's functional data scripting language designed for querying,
+  analyzing, and acting on data.
+menu:
+  v2_0:
+    parent: Query data
+    name: Flux
+    weight: 1
+---
+
+Flux is InfluxData's functional data scripting language designed for querying, analyzing, and acting on data.
+
+## Flux design principles
+Flux is designed to be usable, readable, flexible, composable, testable, contributable, and shareable.
+Its syntax is largely inspired by [2018's most popular scripting language](https://insights.stackoverflow.com/survey/2018#technology),
+Javascript, and takes a functional approach to data exploration and processing.
+
+The following example illustrates querying data stored from the last five minutes,
+filtering by the `cpu` measurement and the `cpu=cpu-usage` tag, windowing the data in 1 minute intervals,
+and calculating the average of each window:
+
+```js
+from(bucket:"example-bucket")
+  |> range(start:-1h)
+  |> filter(fn:(r) =>
+    r._measurement == "cpu" and
+    r.cpu == "cpu-total"
+  )
+  |> aggregateWindow(every: 1m, fn: mean)
+```
+
+## Get started with Flux
+The best way to familiarize yourself with Flux is to walk through creating a simple Flux query.
+
+[Get Started with Flux](/v2.0/query-data/flux/get-started)

content/v2.0/query-data/flux/get-started/_index.md

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+---
+title: Get started with Flux
+description: >
+  Get started with Flux, InfluxData's functional data scripting language.
+  This step-by-step guide through the basics of writing a Flux query.
+menu:
+  v2_0:
+    name: Get started
+    identifier: get-started
+    parent: Flux
+    weight: 2
+---
+
+Flux is InfluxData's new functional data scripting language designed for querying,
+analyzing, and acting on data.
+
+This multi-part getting started guide walks through important concepts related to Flux,
+how to query time series data from InfluxDB using Flux, and introduces Flux syntax and functions.
+
+## Key concepts
+Flux introduces important new concepts you should understand as you get started.
+
+### Pipe-forward operator
+Flux uses pipe-forward operators (`|>`) extensively to chain operations together.
+After each function or operation, Flux returns a table or collection of tables containing data.
+The pipe-forward operator pipes those tables into the next function or operation where
+they are further processed or manipulated.
+
+### Tables
+Flux structures all data in tables.
+When data is streamed from data sources, Flux formats it as annotated
+comma-separated values (CSV), representing tables.
+Functions then manipulate or process them and output new tables.
+
+#### Group keys
+Every table has a **group key** which describes the contents of the table.
+It's a list of columns for which every row in the table will have the same value.
+Columns with unique values in each row are **not** part of the group key.
+
+As functions process and transform data, each modifies the group keys of output tables.
+Understanding how tables and group keys are modified by functions is key to properly
+shaping your data for the desired output.
+
+###### Example group key
+```js
+[_start, _stop, _field, _measurement, host]
+```
+
+Note that `_time` and `_value` are excluded from the example group key because they
+are unique to each row.
+
+## Tools for working with Flux
+
+You have multiple [options for writing and running Flux queries](/flux/v0.12/guides/executing-queries),
+but as you're getting started, we recommend using the following:
+
+### 1. Data Explorer
+The InfluxDB user interface's (UI) Data Explorer makes it easy to build or write
+your first Flux script and visualize the results.
+
+![Flux in the Data Explorer](/img/flux-data-explorer,png)
+
+The Data Explorer provides multiple ways to create Flux queries.
+Toggle between the two with the button to the left of **Submit** in the Data Explorer.
+
+![Flux Query Builder and Script Editor Toggle](/img/flux-ui-toggle.png)
+
+#### Query Builder _(default)_
+The Query Builder is a visual tool for building Flux Queries.
+Select the organization and bucket from which you would like to query data.
+Filter data by any columns available in the data.
+Transform you data using using aggregate functions.
+
+#### Script Editor
+The Script Editor is an in-browser code editor where you can write raw Flux scripts.
+
+### 2. influx CLI
+The [`influx repl` command](/v2.0/reference/cli/influx/repl) opens an interactive
+read-eval-print-loop (REPL) for querying data within an organization in InfluxDB with Flux.
+
+```bash
+influx repl --org org-name
+```
+
+<div class="page-nav-btns">
+  <a class="btn next" href="/v2.0/query-data/flux/get-started/query-influxdb/">Query InfluxDB with Flux</a>
+</div>

content/v2.0/query-data/flux/get-started/query-influxdb.md

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+---
+title: Query InfluxDB with Flux
+description: Learn the basics of using Flux to query data from InfluxDB.
+menu:
+  v2_0:
+    name: Query InfluxDB
+    parent: get-started
+    weight: 1
+---
+
+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()`](#) function defines an InfluxDB data source.
+It requires a [`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 (`|>`) to pipe data from your data source into the [`range()`](/flux/v0.12/functions/transformations/range)
+function, which specifies a time range for your query.
+It accepts two properties: `start` and `stop`.
+Ranges can be **relative** using negative [durations](/flux/v0.12/language/lexical-elements#duration-literals)
+or **absolute** using [timestamps](/flux/v0.12/language/lexical-elements#date-and-time-literals).
+
+###### 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: 2018-11-05T23:30:00Z, stop: 2018-11-06T00:00:00Z)
+```
+
+#### 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 the `filter()` function to narrow results based on data attributes or columns.
+The `filter()` function has one parameter, `fn`, which expects an anonymous function
+with logic that filters data based on columns or attributes.
+
+Flux's anonymous function syntax is similar to Javascript's.
+Records or rows are passed into the `filter()` function as an object (`r`).
+The anonymous function takes the object and evaluates it to see if it matches the defined filters.
+Use the `and` relational operator to chain multiple filters.
+
+```js
+// Pattern
+(r) => (r.objectProperty 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, the `usage_system` field, and the `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
+Use Flux's `yield()` function to output the filtered tables as 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()
+```
+
+{{% note %}}
+Flux automatically assume a `yield()` function at
+the end of each script in order to output and visualize the data.
+`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.
+{{% /note %}}
+
+## Congratulations!
+You have now queried data from InfluxDB using Flux.
+This is a barebones query that can be transformed in other ways.
+
+<div class="page-nav-btns">
+  <a class="btn prev" href="/v2.0/query-data/flux/get-started/">Get started with Flux</a>
+  <a class="btn next" href="/v2.0/query-data/flux/get-started/transform-data/">Transform your data</a>
+</div>

content/v2.0/query-data/flux/get-started/syntax-basics.md

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+---
+title: Flux syntax basics
+description: An introduction to the basic elements of the Flux syntax with real-world application examples.
+menu:
+  v2_0:
+    name: Syntax basics
+    parent: get-started
+    weight: 3
+---
+
+
+Flux, at its core, is a scripting language designed specifically for working with data.
+This guide walks through a handful of simple expressions and how they are handled in Flux.
+
+## Use the influx CLI's REPL
+Use the `influx repl` command to open the interactive read-eval-print-loop (REPL).
+Run the commands provided in this guide in the REPL.
+
+##### Start in the influx CLI in Flux mode
+```bash
+influx repl --org org-name
+```
+
+## Basic Flux syntax
+The code blocks below provide commands that illustrate the basic syntax of Flux.
+Run these commands in the REPL.
+
+### Simple expressions
+Flux is a scripting language that supports basic expressions.
+For example, simple addition:
+
+```js
+> 1 + 1
+2
+```
+
+### Variables
+Assign an expression to a variable using the assignment operator, `=`.
+
+```js
+> s = "this is a string"
+> i = 1 // an integer
+> f = 2.0 // a floating point number
+```
+
+Type the name of a variable to print its value:
+
+```js
+> s
+this is a string
+> i
+1
+> f
+2
+```
+
+### Objects
+Flux also supports objects. Each value in an object can be a different data type.
+
+```js
+> o = {name:"Jim", age: 42}
+```
+
+Use dot notation to access a properties of an object:
+
+```js
+> o.name
+Jim
+> o.age
+42
+```
+
+### Lists
+Flux supports lists. List values must be the same type.
+
+```js
+> n = 4
+> l = [1,2,3,n]
+> l
+[1, 2, 3, 4]
+```
+
+### Functions
+Flux uses functions for most of its heavy lifting.
+Below is a simple function that squares a number, `n`.
+
+```js
+> square = (n) => n * n
+> square(n:3)
+9
+```
+
+{{% note %}}
+Flux does not support positional arguments or parameters.
+Parameters must always be named when calling a function.
+{{% /note %}}
+
+### Pipe-forward operator
+Flux uses the pipe-forward operator (`|>`) extensively to chain operations together.
+After each function or operation, Flux returns a table or collection of tables containing data.
+The pipe-forward operator pipes those tables into the next function where they are further processed or manipulated.
+
+```js
+data |> someFunction() |> anotherFunction()
+```
+
+## Real-world application of basic syntax
+This likely seems familiar if you've already been through through the other
+[getting started guides](/v2.0/query-data/flux/get-started).
+Flux's syntax is inspired by Javascript and other functional scripting languages.
+As you begin to apply these basic principles in real-world use cases such as creating data stream variables,
+custom functions, etc., the power of Flux and its ability to query and process data will become apparent.
+
+The examples below provide both multi-line and single-line versions of each input command.
+Carriage returns in Flux aren't necessary, but do help with readability.
+Both single- and multi-line commands can be copied and pasted into the `influx` CLI running in Flux mode.
+
+### Define data stream variables
+A common use case for variable assignments in Flux is creating variables for one
+or more input data streams.
+
+{{< code-tabs-wrapper >}}
+  {{% code-tabs %}}
+  [Multi-line](#)
+  [Single-line](#)
+  {{% /code-tabs %}}
+{{% code-tab-content %}}
+```js
+timeRange = -1h
+
+cpuUsageUser =
+  from(bucket:"example-bucket")
+    |> range(start: timeRange)
+    |> filter(fn: (r) =>
+      r._measurement == "cpu" and
+      r._field == "usage_user" and
+      r.cpu == "cpu-total"
+    )
+
+memUsagePercent =
+  from(bucket:"example-bucket")
+    |> range(start: timeRange)
+    |> filter(fn: (r) =>
+      r._measurement == "mem" and
+      r._field == "used_percent"
+    )
+```
+{{% /code-tab-content %}}
+
+{{% code-tab-content %}}
+```js
+timeRange = -1h
+cpuUsageUser = from(bucket:"example-bucket") |> range(start: timeRange) |> filter(fn: (r) => r._measurement == "cpu" and r._field == "usage_user" and r.cpu == "cpu-total")
+memUsagePercent = from(bucket:"example-bucket") |> range(start: timeRange) |> filter(fn: (r) => r._measurement == "mem" and r._field == "used_percent")
+```
+{{% /code-tab-content %}}
+{{< /code-tabs-wrapper>}}
+
+These variables can be used in other functions, such as  `join()`, while keeping the syntax minimal and flexible.
+
+### Define custom functions
+Create a function that returns the `N` number rows in the input stream with the highest `_value`s.
+To do this, pass the input stream (`tables`) and the number of results to return (`n`) into a custom function.
+Then using Flux's `sort()` and `limit()` functions to find the top `n` results in the data set.
+
+{{< code-tabs-wrapper >}}
+  {{% code-tabs %}}
+  [Multi-line](#)
+  [Single-line](#)
+  {{% /code-tabs %}}
+{{% code-tab-content %}}
+```js
+topN = (tables=<-, n) =>
+  tables
+    |> sort(desc: true)
+    |> limit(n: n)
+```
+{{% /code-tab-content %}}
+{{% code-tab-content %}}
+```js
+topN = (tables=<-, n) => tables |> sort(desc: true) |> limit(n: n)
+```
+{{% /code-tab-content %}}
+{{< /code-tabs-wrapper >}}
+
+_More information about creating custom functions is available in the [Custom functions](/flux/v0.12/functions/custom-functions) documentation._
+
+Using the `cpuUsageUser` data stream variable defined above, find the top five data
+points with the custom `topN` function and yield the results.
+
+{{< code-tabs-wrapper >}}
+{{% code-tabs %}}
+[Multi-line](#)
+[Single-line](#)
+{{% /code-tabs %}}
+
+{{% code-tab-content %}}
+```js
+cpuUsageUser
+  |> topN(n:5)
+  |> yield()
+```
+{{% /code-tab-content %}}
+
+{{% code-tab-content %}}
+```js
+cpuUsageUser |> topN(n:5) |> yield()
+```
+{{% /code-tab-content %}}
+
+{{< /code-tabs-wrapper>}}
+
+This query will return the five data points with the highest user CPU usage over the last hour.
+
+<div class="page-nav-btns">
+  <a class="btn prev" href="/v2.0/query-data/flux/get-started/transform-data/">Transform your data</a>
+</div>

content/v2.0/query-data/flux/get-started/transform-data.md

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+---
+title: Transform data with Flux
+description: Learn the basics of using Flux to transform data queried from InfluxDB.
+menu:
+  v2_0:
+    name: Transform your data
+    parent: get-started
+    weight: 2
+---
+
+When [querying data from InfluxDB](/v2.0/query-data/flux/get-started/query-influxdb),
+you often need to transform that data in some way.
+Common examples are aggregating data into averages, downsampling data, etc.
+
+This guide demonstrates using [Flux functions](/flux/v0.12/functions) to transform your data.
+It walks through creating a Flux script that partitions data into windows of time,
+averages the `_value`s in each window, and outputs the averages as a new table.
+
+It's important to understand how the "shape" of your data changes through each of these operations.
+
+## Query data
+Use the query built in the previous [Query data from InfluxDB](/v2.0/query-data/flux/get-started/query-influxdb)
+guide, but update the range to pull data from the last hour:
+
+```js
+from(bucket:"example-bucket")
+  |> range(start: -1h)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system" and
+    r.cpu == "cpu-total"
+  )
+```
+
+## Flux functions
+Flux provides a number of functions that perform specific operations, transformations, and tasks.
+You can also [create custom functions](/flux/v0.12/functions/custom-functions) in your Flux queries.
+_Functions are covered in detail in the [Flux functions](/flux/v0.12/functions) documentation._
+
+A common type of function used when transforming data queried from InfluxDB is an aggregate function.
+Aggregate functions take a set of `_value`s in a table, aggregate them, and transform
+them into a new value.
+
+This example uses the [`mean()` function](/flux/v0.12/functions/transformations/aggregates/mean)
+to average values within each time window.
+
+{{% note %}}
+The following example walks through the steps required to window and aggregate data,
+but there is a [`aggregateWindow()` helper function](#helper-functions) that does it for you.
+It's just good to understand the steps in the process.
+{{% /note %}}
+
+## Window your data
+Flux's [`window()` function](/flux/v0.12/functions/transformations/window) partitions records based on a time value.
+Use the `every` parameter to define a duration of each window.
+
+For this example, window data in five minute intervals (`5m`).
+
+```js
+from(bucket:"example-bucket")
+  |> range(start: -1h)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system" and
+    r.cpu == "cpu-total"
+  )
+  |> window(every: 5m)
+```
+
+As data is gathered into windows of time, each window is output as its own table.
+When visualized, each table is assigned a unique color.
+
+![Windowed data tables](/img/flux-windowed-data.png)
+
+## Aggregate windowed data
+Flux aggregate functions take the `_value`s in each table and aggregate them in some way.
+Use the [`mean()` function](/flux/v0.12/functions/transformations/aggregates/mean) to average the `_value`s of each table.
+
+```js
+from(bucket:"example-bucket")
+  |> range(start: -1h)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system" and
+    r.cpu == "cpu-total"
+  )
+  |> window(every: 5m)
+  |> mean()
+```
+
+As rows in each window are aggregated, their output table contains only a single row with the aggregate value.
+Windowed tables are all still separate and, when visualized, will appear as single, unconnected points.
+
+![Windowed aggregate data](/img/flux-windowed-aggregates.png)
+
+## Add times to your aggregates
+As values are aggregated, the resulting tables do not have a `_time` column because
+the records used for the aggregation all have different timestamps.
+Aggregate functions don't infer what time should be used for the aggregate value.
+Therefore the `_time` column is dropped.
+
+A `_time` column is required in the [next operation](#unwindow-aggregate-tables).
+To add one, use the [`duplicate()` function](/flux/v0.12/functions/transformations/duplicate)
+to duplicate the `_stop` column as the `_time` column for each windowed table.
+
+```js
+from(bucket:"example-bucket")
+  |> range(start: -1h)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system" and
+    r.cpu == "cpu-total"
+  )
+  |> window(every: 5m)
+  |> mean()
+  |> duplicate(column: "_stop", as: "_time")
+```
+
+## Unwindow aggregate tables
+
+Use the `window()` function with the `every: inf` parameter to gather all points
+into a single, infinite window.
+
+```js
+from(bucket:"example-bucket")
+  |> range(start: -1h)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system" and
+    r.cpu == "cpu-total"
+  )
+  |> window(every: 5m)
+  |> mean()
+  |> duplicate(column: "_stop", as: "_time")
+  |> window(every: inf)
+```
+
+Once ungrouped and combined into a single table, the aggregate data points will appear connected in your visualization.
+
+![Unwindowed aggregate data](/img/flux-windowed-aggregates-ungrouped.png)
+
+## Helper functions
+This may seem like a lot of coding just to build a query that aggregates data, however going through the
+process helps to understand how data changes "shape" as it is passed through each function.
+
+Flux provides (and allows you to create) "helper" functions that abstract many of these steps.
+The same operation performed in this guide can be accomplished using the
+[`aggregateWindow()` function](/flux/v0.12/functions/transformations/aggregates/aggregatewindow).
+
+```js
+from(bucket:"example-bucket")
+  |> range(start: -1h)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system" and
+    r.cpu == "cpu-total"
+  )
+  |> aggregateWindow(every: 5m, fn: mean)
+```
+
+## Congratulations!
+You have now constructed a Flux query that uses Flux functions to transform your data.
+There are many more ways to manipulate your data using both Flux's primitive functions
+and your own custom functions, but this is a good introduction into the basic syntax and query structure.
+
+---
+
+_For a deeper dive into windowing and aggregating data with example data output for each transformation,
+view the [Windowing and aggregating data](/flux/v0.12/guides/windowing-aggregating) guide._
+
+---
+
+<div class="page-nav-btns">
+  <a class="btn prev" href="/v2.0/query-data/flux/get-started/query-influxdb/">Query InfluxDB</a>
+  <a class="btn next" href="/v2.0/query-data/flux/get-started/syntax-basics/">Syntax basics</a>
+</div>