How do I apply filters to a histogram

[quickqlik2]

I've got data that looks like this, and I'd like to create a histogram showing the number of days "Tickets" have been sitting for customer "A".

Ticket Number	Customer	Status	DateOpened	DaysSitting
0001	A	Open	2021-11-01	30
0002	A	Closed	2021-11-05	26
0003	B	Open	2021-11-06	25
…	…	…	…	...

I've disabled "Include Null Values" and wrote this expression for my histogram bars:

=If(Customer = 'A' and Status = 'Open', DaysSitting, Null())

The histogram doesn't work, and I instead get this error:

The chart is not displayed because it contains only undefined values.

What can I do to create a filtered histogram for the conditions I describe?

[Or · Accepted solution]

Aside from the else condition not being necessary (null() is the default so you could just end the condition after DaysSitting), this works without errors on my end (though the result is less than helpful since it's just a single bar):

Load * INLINE [
Ticket Number, Customer, Status, DateOpened, DaysSitting
0001, A, Open, 2021-11-01, 30
0002, A, Closed, 2021-11-05, 26
0003, B, Open, 2021-11-06, 25
];