How to compute interval value of items

Question

HI,experts,
I have a table with huge amount of data, like this, in source system.
key     month   amount1
A001     2008.1     900
A001     2008.2     1000
A001     2008.4     1100
A002     2008.1     80
A002     2008.2     80
A002     2008.3     90
I want to get a result in my ODS object like below,
key     month   amount1 amount2
A001     2008.1     900     0
A001     2008.2     1000     100
A001     2008.4     1100     100
A002     2008.1     80     0
A002     2008.2     80     0
A002     2008.3     90     10
if first time load.
amount2 = 0
else.
amount2 = amount1 - amount(last time)
endif.
Due to the huge amount of data, I want to use a modelling method in BW via ODS computing without lookup abap coding. Can any help me?

Answer 1

Hello Sam Lu,
There could be several solutions using Non-cumulative key figures but as you want ODS you should create an Update Rule for Key Figure 2 of type "Routine" checking data inserted.
Routine code would be the following:
data: total type f.
select kf1 from /BIC/Ayourodsname00
where Key = comm_structure-key and
         month < sy-datum(6).
total = total + kf1.
endselect.
IF sy-subrc eq 0.
clear result.
else.
result = comm_structure-kf1 - total.
endif.