Modify DAX filter context in Power BI

Lab story

In this lab, you’ll create measures with DAX expressions that involve filter context manipulation.

You learn how to:

Use the CALCULATE function to manipulate filter context.

This lab should take approximately 30 minutes.

Get started

To complete this exercise, first open a web browser and enter the following URL to download the zip file:

https://github.com/MicrosoftLearning/PL-300-Microsoft-Power-BI-Data-Analyst/raw/Main/Allfiles/Labs/05-modify-dax-filter-context/05-modify-dax-filter-context.zip

Extract the file to the C:\Users\Student\Downloads\05-modify-dax-filter-context folder.

Open the 05-Starter-Sales Analysis.pbix file.

Note: You may see a sign-in dialog as the file loads. Select Cancel to dismiss the sign-in dialog. Close any other informational windows. Select Apply Later, if prompted to apply changes.

Create a matrix visual

In this task, you’ll create a matrix visual to support testing your new measures.

In Power BI Desktop, create a new report page.
On Page 3, add a matrix visual.
Resize the matrix visual to fill the entire page.
To configure the matrix visual fields, from the Data pane, drag the Region | Regions hierarchy, and drop it inside the visual.

The labs use a shorthand notation to reference a field or hierarchy. It will look like this: Region | Regions. In this example, Region is the table name and Regions is the hierarchy name._
Add the Sales | Sales field to the Values well.
To expand the entire hierarchy, at the top-right of the matrix visual, select the forked-double arrow icon twice.
To format the visual, in the Visualizations pane, select the Format pane.
In the Search box, enter Layout.
Set the Layout property to Tabular.
Verify that the matrix visual now has 4 column headers.

At Adventure Works, the sales regions are organized into groups, countries, and regions. All countries—except the United States—have just one region, which is named after the country. As the United States is such a large sales territory, it’s divided into five sales regions.

You’ll create various measures in this exercise, and then test them by adding them to the matrix visual.

Manipulate filter context

In this task, you’ll create several measures with DAX expressions that use the CALCULATE function to manipulate filter context.

The CALCULATE function is a powerful function you can use to manipulate the filter context. The first argument takes an expression or a measure (a measure is just a named expression). Subsequent arguments allow modifying the filter context.

Add a measure to the Sales table, based on the following expression:

Note: For your convenience, all DAX definitions in this lab can be copied from the C:\Users\Student\Downloads\05-modify-dax-filter-context\Snippets.txt file.
```
 Sales All Region =
 CALCULATE(
     SUM(Sales[Sales]),
     REMOVEFILTERS(Region)
 )
```
The REMOVEFILTERS function removes active filters. It can take either no arguments, or a table, a column, or multiple columns as its argument.

In this formula, the measure evaluates the sum of the Sales column in a modified filter context, which removes any filters applied to the columns of the Region table.
Add the Sales All Region measure to the matrix visual.
Notice that the measure computes the total of all region sales for each region, country (subtotal) and group (subtotal).

The new measure is yet to deliver a useful result. When the sales for a group, country, or region is divided by this value it will produce a useful ratio known as “percent of grand total”.
In the Data pane, ensure that the Sales All Region measure is selected (when selected, it will have a dark gray background), and then in the formula bar, replace the measure name and formula with the following formula:

Tip: To replace the existing formula, first copy the snippet. Then, select inside the formula bar and press Ctrl+A to select all text. Then, press Ctrl+V to paste the snippet to overwrite the selected text. Then press Enter.
```
 Sales % All Region =
 DIVIDE(
     SUM(Sales[Sales]),
     CALCULATE(
         SUM(Sales[Sales]),
         REMOVEFILTERS(Region)
     )
 )
```
The measure has been renamed to accurately reflect the updated formula. The DIVIDE function divides the sum of the Sales column (not modified by filter context) by the sum of the Sales column in a modified context, which removes any filters applied to the Region table.
In the matrix visual, notice that the measure has been renamed and that a different value now appears for each group, country, and region.
Format the Sales % All Region measure as a percentage with two decimal places.
In the matrix visual, review the Sales % All Region measure values.

Add another measure to the Sales table, based on the following expression, and format as a percentage:

 Sales % Country =
 DIVIDE(
     SUM(Sales[Sales]),
     CALCULATE(
         SUM(Sales[Sales]),
         REMOVEFILTERS(Region[Region])
     )
 )

Notice that the Sales % Country measure formula differs slightly from the Sales % All Region measure formula.

The difference is that the denominator modifies the filter context by removing filters on the Region column of the Region table, not all columns of the Region table. That means that any filters applied to the group or country columns are preserved. It will achieve a result that represents the sales as a percentage of country.
Add the Sales % Country measure to the matrix visual.
Notice that only the regions of the United States produce a value that isn’t 100 percent.

You might recall that only the United States has multiple regions. All other countries comprise a single region, which explains why they’re all 100 percent.
To improve the readability of this measure in visual, overwrite the Sales % Country measure with the following improved formula.
```
 Sales % Country =
 IF(
     ISINSCOPE(Region[Region]),
     DIVIDE(
         SUM(Sales[Sales]),
         CALCULATE(
             SUM(Sales[Sales]),
             REMOVEFILTERS(Region[Region])
         )
     )
 )
```
The IF function uses the ISINSCOPE function to test whether the region column is the level in a hierarchy of levels. When true, the DIVIDE function is evaluated. When false, BLANK is returned because the region column isn’t in scope.
Notice that the Sales % Country measure now only returns a value when a region is in scope.
Add another measure to the Sales table, based on the following expression, and format as a percentage:
```
 Sales % Group =
 DIVIDE(
     SUM(Sales[Sales]),
     CALCULATE(
         SUM(Sales[Sales]),
         REMOVEFILTERS(
             Region[Region],
             Region[Country]
         )
     )
 )
```
To achieve sales as a percentage of group, two filters can be applied to effectively remove the filters on two columns.
Add the Sales % Group measure to the matrix visual.

To improve the readability of this measure in visual, overwrite the Sales % Group measure with the following formula.

 Sales % Group =
 IF(
     ISINSCOPE(Region[Region])
         || ISINSCOPE(Region[Country]),
     DIVIDE(
         SUM(Sales[Sales]),
         CALCULATE(
             SUM(Sales[Sales]),
             REMOVEFILTERS(
                 Region[Region],
                 Region[Country]
             )
         )
     )
 )

Notice that the Sales % Group measure now only returns a value when a region or country is in scope.
In Model view, place the three new measures into a display folder named Ratios.
Save the Power BI Desktop file.

The measures added to the Sales table have modified filter context to achieve hierarchical navigation. Notice that the pattern to achieve the calculation of a subtotal requires removing some columns from the filter context, and to arrive at a grand total, all columns must be removed.

Lab complete

You may choose to save your Power BI report, though it’s not necessary for this lab. In the next exercise, you’ll work with a pre-made starter file.

Navigate to the “File” menu in the top left corner and select “Save As”.
Select Browse this device.
Select the folder where you want to save the file and give it a descriptive name.
Select the Save button to save your report as a .pbix file.
If a dialog box appears prompting you to apply pending query changes, select Apply.
Close Power BI Desktop.