Is aggr() the way to create this expression?

[#1]

Given a call_fact table as follows:

Call ID	Transaction Key
555-1212	12345
555-1122	6789

And a transaction table (with non-unique keys) as follows:

Tansaction Key	Transaction Type	Transaction Value
12345	Request Info	Cruise
12345	Make Reservation	Guarranteed
6789	Request Info	Cruise
6789	Cancel Reservation	Cancelled

How would I define an expression that would count all of the calls that Requested Info about a Cruise AND Made a Guaranteed Reservation.

In the above example, the answer should be '1'.        

I have a feeling the aggr() function should be employed here, but I'm not sure how.

Thanks.

[Gysbert_Wassenaar]

You can do it with a set analysis expression. Something like this:

=count({<Type={'Request Info'},Value={'Cruise'},[Call ID]=p({<Type={'Make Reservation'},Value={'Guarranteed'}>}[Call ID])>} distinct Key)

See attached example.