Use parameters in Azure Data Explorer dashboards

Parameters are used as building blocks for filters in Azure Data Explorer dashboards. They're managed in the dashboard scope, and can be added to queries to filter the data presented by the underlying visual. A query can use one or more parameters.

This document describes the creation and use of parameters and linked filters in dashboards. Parameters can be used to filter dashboard visuals either by selecting parameter values in the filter bar or by using cross-filters.

The query examples used in this article are based on the StormEvents table in the samples gallery.

Note

Parameter management is available in Editing mode to dashboard editors.

Prerequisites

• Visualize data with Azure Data Explorer dashboards
• Editor permissions on an Azure Data Explorer dashboard
• A dashboard with visuals

View parameters list

To view the list of all dashboard parameters, select the Parameters button at the top of the dashboard.

Create a parameter

To create a parameter:

1. Switch from Viewing to Editing mode.

   

2. Select the Parameters button at the top of the dashboard.

   

3. Select the + New parameter button at the top of the right pane.

4. Fill in the relevant properties for your parameter.

Supported properties

In the Add parameter pane, configure the following properties:

Field	Description
Label	The name of the parameter shown on the dashboard or the edit card.
Parameter type	One of the following parameters: Single selection: Only one value can be selected in the filter as input for the parameter. Multiple selection: One or more values can be selected in the filter as input(s) for the parameter. Time range: Allows creating additional parameters to filter the queries and dashboards based on time. Every dashboard has a time range picker by default. Free text: Doesn't have any values populated in the filter. The user can type a value or copy/paste a value to the text field. The filter keeps the recent values used.
Variable name	The name of the parameter to be used in the query. Tip: Prefixing variable names with a distinctive character, such as an underscore character (_), makes them easier to find when writing queries.
Data type	The data type of the parameter values.
Show on pages	Select the pages where this parameter will be displayed. The Select all option shows the parameter on all pages.
Source	The source of the parameter values: Fixed values: Manually introduced static filter values. Query: Dynamically introduced values using a KQL query.
Default value	The default value of the filter. The filter will start always with the default value upon initial rendering of the dashboard.
Add a "Select all" value	Applicable only to single selection and multiple selection parameter types. Used to retrieve data for all the parameter values. This value should be built into the query to provide the functionality. For more examples of building such queries, see Use the multiple-selection query-based parameter.

Manage parameters

After selecting Parameters from the top bar, you can view the list of existing parameters. In each parameter card, select the pencil widget to edit the parameter or select the More [...] menu to Duplicate, Delete, or move the parameter.

The following indicators can be viewed in the parameter card:

• Parameter display name
• Variable names
• Number of queries in which the parameter was used
• Pages the parameter is pinned to

The parameter cards can be ordered by drag and drop or by using the Move to > option and selecting the new location.

Use parameters in your query

A parameter must be used in the query to make the filter applicable for that query visual. Once defined, you can see the parameters in the Query page > filter top bar and in the query intellisense.

Note

If the parameter isn't used in the query, the filter remains inactive. Once the parameter is added to the query, the filter becomes active.

Parameter types

Several dashboard parameter types are supported, as follows:

• Default time range parameter
• Single-selection fixed-values parameters
• Multiple-selection fixed-values parameters
• Single-selection query-based parameters
• Multiple-selection query-based parameters
• Free text parameters
• Data source parameters

The following examples describe how to use parameters in a query for various parameter types.

Default time range parameter

Every dashboard has a Time range parameter by default. It shows up on the dashboard as a filter only when used in a query. Use the parameter keywords _startTime and _endTime to use the default time range parameter in a query as seen in the following example:

StormEvents
| where StartTime between (_startTime.._endTime)
| summarize TotalEvents = count() by State
| top 5 by TotalEvents

Once saved, the time range filter shows up on the dashboard. Now it can be used to filter the data on the card. You can filter your dashboard by selecting from the drop-down: Time range (last x minutes/hours/days) or a Custom time range.

Single-selection fixed-values parameters

Fixed value parameters are based on predefined values specified by the user. The following example shows you how to create a single selection fixed value parameter.

Create a single-selection fixed-values parameter

1. Select Parameters to open the Parameters pane and select New parameter.

2. Fill in the details as follows:

   • Label: Event Type

   • Parameter type: Single selection

   • Variable name: _eventType

   • Data type: String

   • Pin as dashboard filter: checked

   • Source: Fixed values

     In this example, use the following values:

     Value	Parameter display name
     Thunderstorm Wind	Thunderstorm wind
     Hail	Hail
     Flash Flood	Flash flood
     Drought	Drought
     Winter Weather	Winter weather

   • Add a Select all value: Unchecked

   • Default value: Thunderstorm Wind

3. Select Done to create the parameter.

The parameter can be seen in the Parameters side pane, but aren't currently being used in any visuals.

Use a single-selection fixed-values parameter

1. Run a sample query using the new Event TypTope parameter by using the _eventType variable name:

   StormEvents
   | where StartTime between (_startTime.._endTime)
   | where EventType == _eventType
   | summarize TotalEvents = count() by State
   | top 5 by TotalEvents
   

   The new parameter shows up in the parameter list at the top of the dashboard.

2. Select different values to update the visuals.

   

Multiple-selection fixed-values parameters

Fixed value parameters are based on predefined values specified by the user. The following example shows you how to create and use a multiple-selection fixed-value parameter.

Create a multiple-selection fixed-values parameters

1. Select Parameters to open the Parameters pane and select New parameter.

2. Fill in the details as mentioned in Use a single-selection fixed-values parameter with the following changes:

   • Label: Event Type
   • Parameter type: Multiple selection
   • Variable name: _eventType

3. Select Done to create the parameter.

The new parameters can be seen in the Parameters side pane, but aren't currently being used in any visuals.

Use a multiple-selection fixed-values parameter

1. Run a sample query using the new Event Type parameter by using the _eventType variable.

   StormEvents
   | where StartTime between (_startTime.._endTime)
   | where EventType in (_eventType) or isempty(_eventType)
   | summarize TotalEvents = count() by State
   | top 5 by TotalEvents
   

   The new parameter shows up in the parameter list at the top of the dashboard.

2. Select one or more different values to update the visuals.

   

Single-selection query-based parameters

Query-based parameter values are retrieved during dashboard loading by executing the parameter query. The following example shows you how to create and use a single selection query-based parameter.

Create a single-selection query-based parameter

1. Select Parameters to open the Parameters pane and select New parameter.

2. Fill in the details as mentioned in Use a single-selection fixed-values parameter with the following changes:

   • Label: State

   • Variable name: _state

   • Source: Query

   • Data source: StormEventsSample

   • Select Edit query and enter the following query. Select Done.

     StormEvents
     | where StartTime between (_startTime.._endTime)
     | where EventType in (_eventType) or isempty(_eventType)
     | summarize TotalEvents = count() by State
     | top 5 by TotalEvents
     | project State
     

   • Value: State

   • Display name: State

   • Default value: Choose a default value

3. Select Done to create the parameter.

Use a single-selection query-based parameter

1. The following sample query with the new State parameter uses the _state variable:

   StormEvents
   | where StartTime between (_startTime.._endTime)
   | where EventType in (_eventType) or isempty(_eventType)
   | where State == _state
   | summarize TotalEvents = count() by State
   | top 5 by TotalEvents
   

   The new parameter shows up in the parameter list at the top of the dashboard.

2. Select different values to update the visuals.

Multiple-selection query-based parameters

Query-based parameter values are derived at dashboard load time by executing the user specified query. The following example shows how to can create a multiple-selection query-based parameter:

Create a multiple-selection query-based parameter

1. Select Parameters to open the Parameters pane and select + New parameter.

2. 1. Fill in the details as mentioned in Use a single-selection fixed-values parameter with the following changes:
   • Label: State
   • Parameter type: Multiple selection
   • Variable name: _state

3. Select Done to create the parameter.

Use a multiple-selection query-based parameter

1. The following sample query uses the new State parameter by using the _state variable.

   StormEvents
   | where StartTime between (_startTime.._endTime)
   | where EventType in (_eventType) or isempty(_eventType)
   | where State in (_state) or isempty(_state)
   | summarize TotalEvents = count() by State
   | top 5 by TotalEvents
   

   Note

   This sample uses the Select All option by checking for empty values with the isempty() function.

   The new parameter shows up in the parameter list at the top of the dashboard.

2. Select one or more different values to update the visuals.

Free text parameters

Free text parameters don't contain any values. They allow you to introduce your own value.

Create a free text parameter

1. Select Parameters to open the Parameters pane and select + New parameter.

2. Fill in the details as follows:

   • Label: State
   • Parameter type: Free text
   • Variable name: _state
   • Data type: String
   • Default value: No default value

Use a free text parameter

1. Run a sample query using the new State parameter by using the _state variable name:

   StormEvents
   | where StartTime between (_startTime.._endTime)
   | where EventType in (_eventType) or isempty(_eventType)
   | where State contains _state
   | summarize TotalEvents = count() by State
   | top 5 by TotalEvents
   

Data source parameters

Once you have added data sources to your dashboard, you can create a parameter that selects one or more of the available data sources. This parameter can be used in tiles and other parameters.

Create a data source parameter

1. Select Parameters to open the Parameters pane and select + New parameter.

2. Fill in the details as follows:

   • Label: Source
   • Parameter type: Data source
   • Show on pages: Select all
   • Values: Select all
   • Default value: StormEventsSample

3. Select Done.

The new parameter is now visible in the parameter list at the top of the dashboard.

Use a data source parameter

1. Navigate to the query of a new or existing tile.

2. In Source, select the name of your new parameter under Data source parameters. For the above-created parameter, select Cluster.

3. Select Apply changes.

4. Use the Cluster parameter to change the data source for this connected query.

Cross-filters parameters

Cross-filters allow you to select a value in one visual and all dashboard visuals, such as line or scatter charts, are filtered to only show related data. Using cross-filters achieves the same result as selecting the equivalent value for the parameter in the parameter list at the top of the dashboard.

Define cross-filters

To create a cross-filter, you must turn on the option in the visual, and then specify the parameter that is used to filter the data.

1. Navigate to the query of the tile where you want to add cross-filters.

2. Select Visual.

3. In the right pane, select Interactions, and then turn on cross-filters.

4. Optionally, specify the Interaction type. The default is Point where you can select a value in the visual. For selecting a range of values, such as in a time chart, select Drag.

5. Specify both the column that is used to provide the value and a parameter used to filter the query.

   Important

   The column and parameter must be of the same data type.

Interact with your data using cross-filter

Once the cross-filter is defined, you can use it to interact with your data. In visuals where you've defined cross-filters, you can select data points and use their values to filter the current dashboard page. For table visuals, select data points by right-clicking on the relevant cell and then in the context menu, select Cross-filter.

You can reset the cross-filter by selecting Reset at the top of the visual where it was selected.

Use drillthroughs as dashboard parameters

With drillthrough, you can select a value in a visual and use it to filter the visuals in a target page in the same dashboard. When the target page opens, the value is preselected in the relevant filters. The visuals on the page, such as line or scatter charts, are filtered to only show related data.

Define a drillthrough

To create a drillthrough, you must first turn it on in the visual and then add one or more drillthroughs as required.

1. Edit the visual where you want to add a drillthrough. Make sure that the Visual tab is selected.

2. In the right pane, select Interactions, then turn on drillthrough.

   

3. Under Drillthrough, select Create new, and specify the following information. Optionally select Add another pair to add multiple parameters for a target page. Repeat this step to add drillthroughs to other pages in the current dashboard using different parameters.

   Field	Description
   Destination page	One or more target pages to drill through to using the defined parameters.
   Column	The query result's column to use as the value for a parameter in the target page.
   Parameter	The parameter used to filter visuals in the target page using the column value.
   Notes	Optional short description.

   Important

   Column and parameter pairs must be of the same data type.

Interact with your data using drillthroughs

Once drillthroughs are defined, you can use them to interact with your data. To do so, in visuals or tables where you've defined a drillthrough, right-click on a data point, and then select Drill through to > destination page. The values from the data point will be used as the parameters to filter the visuals on the target page.

To return to the source page, in the top-right of the destination page, select Reset. All filters assigned by the drillthrough will be reset.

Use filter search for single and multiple selection filters

In single and multiple selection filters, type the value that you want. The filter updates to only show the values that match the search term.

Related content

• Customize Azure Data Explorer dashboard visuals
• Write Kusto Query Language queries in the web UI