How to get pivot table showing 'missing' dates as 'x' instead of '-'

[DutchArjo]

I have a table with peoples presence at certain dates. Of course, sometimes people are not available and they are missing in the input table.

I want to create an overview, showing when people were present or not with the specific dates in the columns and as values either "v" (when present) or "x" when absent.

I thought I learned how to do so in the Udemy Qlik Sense course, but apparently, I haven't been paying enough attention or I am applying it in the wrong way.

So can someone help me with the right approach?

In the source table, presence is noted like below:

So for every single person, the presence is noted per date. People who were not present are no noted for that date.

I created the pivot like this:

On the left are the names and registration numbers of the people.

I created a new measure for the pivot with this expression:

if(count(appel_datum)>0,'v','x')

But as you can see only the dates when people are present are in the pivot. When people were not present, there is only the dash sign.

I also used tried this expression:

if(isnull(appel_datum)<>-1,'v','x') (unchecked 'show nulls').

How can I get Qlik Sense to show an "x" for the date a person was not present (and therefore is not in the source table)?

[Anil_Babu_Samineni]

Apologies for the delay, Do you still need input on this? Otherwise Please accept your solution as answered.