error in update rules

Hi,

i written routine in update rules of the ods. I am loading data from r/3 to 1st ods and from 1st ods to 2nd ods. In the update rules of 1st ods my routine is calculating the date_diff of two date fields. I am getting the output for some values like 12-,13- etc. In the 2nd ods update rules my routine is to get result based on the output of the above routine

for eg: if date_diff < 0,result = 0,

elseif date_diff = 0,result = 1.

elseif date_diff > 0, result = 2.

but i am getting the output as blank space for date_diff < 0 and for others it is working fine. How to solve this ?

Any help will be appreciated.