Problem with changing value on specific date
I am a first time user of this forum. I am new to FileMaker Pro however I have recently completed a personal database for billing of services to my local hospital.
Each service has a total amount of units. The service cost is the total units *$36.85. This unit value increases by 3% on the 1st of November each year. Obviously by changing this figure in the calculation will change all previously entered services. I have tried making a unit cost table and using a Lookup. I know with a Lookup any change to the value in the table won't change any previous services For some reason I can't get this to work, it keeps returning an empty field . Is it possible to right a script for the unit price field?
Appreciate that it is probably an easy fix .