Add conditions within a simple calculation - conditional-statements

Question

I calculated a simple addition but want to add a condition in it;
1*(acute_miorhistory_mi) +
1*(chf) +
1*(pvd) +
1*(cvd) +
1*(copd) +
1*(dementia) +
2*(paralysis) +
1*(diabetes) +
2*(diabetes_comp) +
2*(renal_disease) +
1*(mild_liver_disease) +
3*(liver_disease) +
1*(ulcers) +
1*(rheum_disease) +
6*(aids) +
2*(carcinoma) +
6*(metacancer).
what I want to do is to:
not add diabetes if diabetes_comp exists
not add mild_liver_disease if liver_disease exist
not to add carcinoma if metacancer exists.
so how to add if command here?

Answer 1

Here's a nice way to add the conditions you need without changing the structure of your original command.
So the condition for adding carcinoma is that metacancer doesn't exist, or if carcinoma=0. In spss you can use (carcinoma=0) as a numerical value of 0 (true) or 1 (false):
1*(acute_miorhistory_mi) +
. . .
1*(diabetes)*(diabetes_comp=0) +
2*(diabetes_comp) +
2*(renal_disease) +
1*(mild_liver_disease)*(liver_disease=0) +
3*(liver_disease) +
. . .
2*(carcinoma)*(metacancer=0) +
6*(metacancer).