Table with 'blanks' and calculating 'Coverage' based on customers, calls and time

First point is to obtain this values in the visual, right?

Desired table

You need to select "Show items with no value"

Then, for the calculation you need, you can write this measure

DIVIDE (

      DISTINCTCOUNT ( Fact[Customer] ),
      COUNTROWS ( Customer )
)

Pay attention to one detail, should you apply filters to a dimension (ex a period selected in the Calendar ), this would affect only the DISTINCTCOUNT ( Fact[Customer] ) and not the COUNTROWS ( Customer ) so this calculation whould be used carefully

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Consider voting this Power BI idea

Francesco Bergamaschi

MBA, M.Eng, M.Econ, Professor of BI

Hi Raketenrudi ,
Thank you for reaching out to Microsoft fabric community forum.

Follow these steps to achieve your desired result - 
Create Relationship

Drag Customer[Customer ID] to Calls[Customer ID]

Keep it 1 to many, single direction

Create Measures - 
Call Count Measure

Call Count :=
CALCULATE(
COUNTROWS('Calls'),
FILTER(
ALL('Calls'),
'Calls'[Customer ID] = SELECTEDVALUE('Customer'[Customer ID])
)
)

Last Call Date Measure
Last Call Date :=
VAR LastDate =
CALCULATE(
MAX('Calls'[Date]),
FILTER(
ALL('Calls'),
'Calls'[Customer ID] = SELECTEDVALUE('Customer'[Customer ID])
)
)
RETURN
IF(LastDate <> BLANK(), LastDate, "none")

Coverage Measure
Coverage % :=
VAR TotalCustomers = COUNTROWS(Customer)
VAR ContactedCustomers =
CALCULATE(
COUNTROWS(Customer),
FILTER(Customer, [Call Count] > 0)
)
RETURN
FORMAT(DIVIDE(ContactedCustomers, TotalCustomers), "0.0%")

Create Visual
Insert a Table visual

Add these fields from Customer table:

Customer ID

[Last Call Date] (measure)

[Call Count] (measure)

Add Slicers (Optional)
Add slicers for Calls[Date] and/or Calls[Product]
The logic will dynamically reflect the customer call history as per slicer filter.

Add KPI Card for Coverage
Add a Card visual - keep [Coverage %]

Please find the below attached .pbix file for your reference.

Regards,
Sreeteja.

Hi Elena_Kalina FBergamaschi Anonymous ,

thank you for sharing your ideas. The combination led me to the solution of the problem. 

All of your proposals work for the small table - but since I have this big table, the CALCULATE expressions does not work, if I want to show them in the table. I.e. the call count including zeros. I get the error message 'exceding ressources'. BUT it works if applied to the general filter setting of the visual.

1.  Use a one directional relation from table 'customer' to table 'calls'.
2. Set up a straightforward measure for coverage: DISTINCTCOUNT(calls[Customer ID] )/ DISTINCTCOUNT(customers[Customer ID]). This works due to the above mentioned relation. (Note: Nesting in to a CALCULATE expression defining the cross filter method is also working)
3. To show the entries of customers with no calls - considering all other filters applied - I set up another measure 'check_if_exists' evaluating an IF statement. The statement returns 'N' if no calls exist. 
4. Apply 'check_if_exists' to the visual filter settings. The result is a table containing only customers with zero calls. (Note: The measure cannot be applied to the visual itself, as I wanted in the beginning, due to the size of the table)

Thanks again and hopefully it helps somebody else out there as well 🙂