An Introduction to Parameters in Power BI

How to Connect to Data in Power BI Desktop

Click on the New Parameter card and then click on Numeric Range in the dropdown. Let’s use a parameter to compare product sales with discounts. Name your parameter ‘Discount Parameter’ and change the Data type to ‘Decimal number’. Set the Minimum to 0, Maximum to 0.75, and Increment to 0.05. If you want a slicer to be added to your page with your new parameter, keep the ‘Add slicer to page box’ checked. 

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Once you click on New measure, a popup window will appear at the top of your screen where you are able to use the DAX language to create a custom measure. We will use the following formula for our Sales Amount_discounted measure:

Sales Amount_discounted = SUM(Sales[Sales Amount]) – (SUM(Sales[Sales Amount]) * ‘Discount Parameter’[Discount Value])

This measure will link our parameter with our bar chart visual and will update when changes are made within the slider.

Creating a field in Power BI Desktop

In the Modeling tab, click on ‘New parameter’ and then click on ‘Fields’ in the dropdown. Name it Field Parameter and drag in the Category, Subcategory, Model, and Product fields. Like before, leave the ‘Add slicer to this page’ box checked and click on Create.

Since the data in this slicer isn’t numeric, you’ll see the slicer populate as a checklist. 

Now let’s add a column chart to our report page. For our x-axis, drag in the Field Parameter field from the Data pane. In the y-axis, drag in Profit. With no selection in our parameter, the visual should default to the first field in your field parameter. In our case, this is the Category field. 

Field parameters in Power BI are a little easier to create than numeric parameters, since you don’t have to create a custom measure to actually use the parameter, they automatically use the fields in your data. 

Editing your field parameters

Let’s say we forgot to add the Color field from the Products table to our field parameter. To edit your parameter after it has been created, expand your Field Parameter in the Data pane and click on the measure in your field parameter.

Once you do so, the DAX for that Field Parameter column will appear at the top of your screen. Now we follow the formatting and add the Color field.

The parameter column structure is: 

(“Name of column in the parameter”, NAMEOF(‘table’[Column]), order) 

Let’s say I would like to add color as a fifth option. Before I hit Shift+Enter to create a new line under the Product line, I add a comma to the Product line since it is no longer the last line in the code. Then I insert the Color line with the same syntax as the first four options. Once I hit enter, the slicer automatically updates to include the new column.

You can add, remove, reorder, and rename your parameters in your slicer in this DAX window. 

Thanks for reading the basics of using numeric and field parameters in Power BI Desktop!

Juan Carlos Guzman