Query definition - exclusion of calculated formulas
I have a formula 1 and a formula 2.
Let's say formula 1 has the result 1 = 100
On the other hand formula 2 has the result 2 = 30.
Another formula 3 subtracts the values of both formulas, 1 and 2, result 3 = 70.
Formula 1, result 1 = 100
Formula 2, result 2 = ' '
As we can see, result 2 has no values as there are no records available in the InfoCube.
Now I would like to calculate formula 3 in the way, that this constellation of result 1 (=100) and result 2 (=' ') is ignored. That means there should be NO value be calculated for result 3.
How can this be achieved?