In truth, you should be using Primary keys for all your tables (auto-enter serial numbers) and then you can easily reference that number. Let's say you are number 5, it would be:
If ( GuestID = 5 ; 0 ; 125 )
... or then using your example:
If ( GuestName <> "Janet" ; 125 )
If no default result is specified, it is assumed blank. So in the second example, I left off the 0 result and the calc will produce blank on "Janet". A number field does NOT need a zero. If you want the zero, it can be reversed as well as the above as:
If ( GuestName = "Janet" ; 0 ; 125 )
... but what happens if you rent to someone else named Janet? This is the reason that your Guests table should have one record per unique guest so you can have two Janets, each with different apartment numbers and you can tell them apart in things such as relationships and calculations (as I explained in the first calculation).
I hope this gets you moving forward. :^)
CORRECTION: Added part in blue to correct a typo
your answer was perfect. THank you. NOt only did you provide a solution, but you gave me a good recommendation about the serial numbers. Just seeing an actual example of the string was most helpful.
It is working now the way I want it now.
I have other problems gettign up to speed with this program. My reports don't do what I want and it seems like I keep changing the formats of the fileds over and over again to reflect dollars. Ideally I would like to hire a consultant for about an hour to help me set up my system. Are you interested in somethng like that?
I have sent you a private message.