I'm very inexperienced, so your answer makes me a little confused.
The line in the invoice to which I refer looks like this:
"Rebate" =[Rebate] "%" "Reduction" =[Rebate]*[Sum Costs]
Where shall I place this logical sentence, and will the whole line disappear if it is zero?
Is there a way of omitting both label and the data itself if the value of it is e.g. zero? I would like to print invoices, but if the rebate value or the transport cost is zero, that line in the invoice should not appear in the report.