Help regarding a calculation logic

[#1]

Hi Everybody,
I am having a problem regarding a calculation. Please go through the data and the explanations given below and let me know how I can go forward with the calculation logic. Below given is the data which is used for the same.
YearMonth	Product	SalesOrder	RentalAmount	CancelFlag
201004	QlikView9.0	SR1	100,000
201004	QlikView9.0	SR2	200,000
201004	QlikView9.0	SR3	300,000
201004	QlikView9.0	SR4	400,000
201005	QlikView9.0	SR1	100,000
201005	QlikView9.0	SR2	100,000	A
201005	QlikView9.0	SR3	0	C
201005	QlikView9.0	SR4	400,000
201006	QlikView9.0	SR1	50,000	A
201006	QlikView9.0	SR2	100,000
201006	QlikView9.0	SR4	400,000
201007	QlikView9.0	SR1	50,000
201007	QlikView9.0	SR2	100,000
201007	QlikView9.0	SR4	0	K
where in cancellation flag A,C and K means cancellation criterias for different orders. The Cancellation logic is done as given below.
The cancellation amount is calculated for all the products whose cancellation flag is set.
so for the product QlikView 9.0 in the yearmonth 201005 SalesOrder SR2 is cancelled. For this calculation is done like
200000 - 100000 = 100000 where 200000 is the previous year months rental and 100000 is the current yearmonths rental. Similarly, for product QlikView 9.0 in year month 201005 SalesOrder SR3, the cancellaton amount is 300000 - 0 = 300000.
that is Calculation Amount = previous Yearmonths rental amount for which cancellation flag exists in the next month- Current Yearmonths Rental amount for which Cancellation flag exists.
Please give me some pointers in how to calculate the cancellation amount if possible in the modelling level or in the reporting side.
Thanks to all the people in advance for extending you help.
Thanks and Regards
Robin

[#2]

Hi Robin, Please visit this link http://community.qlik.com/forums/t/27247.aspx. John have given some solution for the same problem which you are facing. Regards, Ravi

[#3]

Hi Robin, Please visit this link http://community.qlik.com/forums/t/27247.aspx. John have given some solution for the same problem which you are facing.

Regards,

Ravi