Handling Different Granularities In Power BI Using Slicer Groups

Reading Prathy Kamasani’s excellent blog post on Sync Slicers the other week I had a revelation: in the post Prathy shows how it is possible to sync selections between two slicers that are based on different columns from different tables in your dataset, something I had not known was possible. As soon as I read this, I realised this technique could be used to solve a number of common problems including that of handling data at different granularities.

This problem has been written about extensively over the years by Marco Russo and Alberto Ferrari in the following articles, which are all worth reading for background:

https://www.daxpatterns.com/handling-different-granularities/

https://www.sqlbi.com/articles/physical-and-virtual-relationships-in-dax/

https://www.sqlbi.com/articles/propagate-filters-using-treatas-in-dax/

Let me be clear: the solution I’m showing in this post is not the “best”, fastest or most elegant solution to this problem. It does, however, have the advantage of not requiring any changes to relationships or the DAX of your measures – and this could be important in scenarios when making these changes would be time-consuming or have other knock-on effects.

Now, consider the following dataset:

image

There is a Date dimension table and a relationship has been built between it and the Daily Sales table, which contains sales information at the date granularity. There is also a Monthly Budget table that contains data at the Month granularity, and no relationship between it and the Date dimension table. The requirement is, however, to be able to select a month on the Date dimension table and for this selection to filter the Daily Sales table and the Monthly Budget table.

Now look at the following report. With two slicers built from the Month columns of the Date and Monthly Budget tables, selecting a month from the slicer built on the Month column of the Date table filters the sales value but not the Budget value, as you would expect:

SynchSlicersNoSynch

The key thing is that the two Month columns contain month names in exactly the same format, “MonthName Year”, which means that a selection on one can be transferred over to the other. Next, for both slicers on the report, go to the Sync Slicers pane, expand the Advanced options section and enter the same group name for both. Make sure the “Sync field changes to other slicers” option is selected too.

image

Once you’ve done this you’ll find that the selection on the slicer built on the Date table is transferred to the slicer built on the Monthly Budget table, even though there is no relationship between them and no clever DAX used, and this in turn means that both the Budget and the Sales values shown are affected:

SynchSlicersWithSynch

The last step is to hide the slicer for the Month column on the Monthly Budget table so the user only sees the slicer for the Month column on the Date table. You can do this either on the Selection pane or by deselecting the “eye” option on the Sync Slicers pane:

image

The end result is this:

SynchSlicersWithSynchHidden

One last thing to mention is that, if you look at the DAX queries generated behind the scenes, it’s all done using the TreatAs function. Here’s an example of a query that shows this:

DEFINE
  VAR __DS0FilterTable =
    TREATAS({"December 2019"}, 'Monthly Budget'[Month])

  VAR __DS0FilterTable2 =
    TREATAS({"December 2019"}, 'Date'[Month])

EVALUATE
  SUMMARIZECOLUMNS(
    __DS0FilterTable,
    __DS0FilterTable2,
    "SumBudget", IGNORE(CALCULATE(SUM('Monthly Budget'[Budget])))
  )

You can download the sample pbix file for this post here.

3 responses

  1. This is great but sync slicers does not seem to work with custom visuals like Chiclet slicers – which is a pity
    Also IGNORE – did not know such a function existed.

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