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Documentation Grafana documentation Data sources InfluxDB Template variables

InfluxDB template variables

Instead of hard-coding details such as server, application, and sensor names in metric queries, you can use variables. Grafana displays these variables in drop-down select boxes at the top of the dashboard to help you change the data displayed in your dashboard. Grafana refers to such variables as template variables.

For general information about variables, refer to Variables and Add and manage variables.

Before you begin

• Configure the InfluxDB data source.
• Understand Grafana template variables.

Supported variable types

Create a query variable

By adding a query template variable, you can write an InfluxDB metadata exploration query. These queries return results such as measurement names, key names, and key values.

For more information, refer to Add a query variable.

InfluxQL query variable examples

To create a variable containing all values for the hostname tag, use the following query in the Query field:

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SHOW TAG VALUES WITH KEY = "hostname"

You can fetch key names for a given measurement:

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SHOW TAG KEYS [FROM <measurement_name>]

You can list available measurements:

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SHOW MEASUREMENTS

Flux query variable examples

For Flux-configured data sources, write a Flux query that returns a single column of values:

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import "influxdata/influxdb/schema"
schema.tagValues(bucket: v.defaultBucket, tag: "hostname")

SQL query variable examples

For SQL-configured data sources (InfluxDB 3.x), write an SQL query that returns a single column of values:

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SELECT DISTINCT hostname FROM cpu

You can list available tables:

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SHOW TABLES

You can list columns in a specific table:

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SHOW COLUMNS FROM cpu

Chain or nest variables

You can create nested variables, sometimes called chained variables.

For example, if you have a variable named region, you can configure the hosts variable to display only hosts from the selected region.

InfluxQL:

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SHOW TAG VALUES WITH KEY = "hostname"  WHERE region = '$region'

SQL:

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SELECT DISTINCT hostname FROM cpu WHERE region = '$region'

If you have a variable containing key names, you can use it in a GROUP BY clause. This allows you to adjust the grouping by selecting from the variable list at the top of the dashboard.

Use Ad hoc filters

InfluxDB supports the Ad hoc filters variable type for InfluxQL. This variable type allows you to define multiple key/value filters, which Grafana automatically applies to all your InfluxDB queries. Ad hoc filters also support expressions.

To add Ad hoc filters:

1. Navigate to Dashboard settings > Variables.
2. Click Add variable.
3. Select Ad hoc filters as the variable type.
4. Select your InfluxDB data source.

For more information, refer to Add free-form filters.

Choose a variable syntax

The InfluxDB data source supports two variable syntaxes for use in the Query field:

• $<varname> - Use this syntax for standalone variable references. It doesn’t allow you to use a variable in the middle of a word or expression.
• ${varname} - Use this syntax when you want to interpolate a variable in the middle of an expression.

InfluxQL examples:

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SELECT mean("value") FROM "logins" WHERE "hostname" =~ /^$host$/ AND $timeFilter GROUP BY time($__interval), "hostname"

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SELECT mean("value") FROM "logins" WHERE "hostname" =~ /^${host}$/ AND $timeFilter GROUP BY time($__interval), "hostname"

When you enable the Multi-value or Include all value options with InfluxQL, Grafana converts the labels from plain text to a regular expression-compatible string, so you must use =~ instead of =.

SQL examples:

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SELECT $__dateBin(time), mean(usage_system) FROM cpu WHERE $__timeFilter(time) AND host = '$host' GROUP BY $__dateBin(time)

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SELECT $__dateBin(time), mean(usage_system) FROM cpu WHERE $__timeFilter(time) AND host IN ($host) GROUP BY $__dateBin(time)

When you enable the Multi-value option with SQL, use the IN operator instead of = to match multiple values.

Templated dashboard example

To view an example of a templated dashboard, refer to this InfluxDB example dashboard.