Table Calculation In Blended Data Sources

Question

I have 2 data sources:

1) Eligible Devices to be changed to a newer model

2) Devices actually changed to a new model

These could be for example computer devices which are after a certain time required to be changed to a newer version ie end of life of a product.

As this is a blended data source, so i cannot apply an LOD.

The calculation i am trying to achieve is:

Jan 2017: There are 100 eligible devices but actually only 85 got refreshed. hence there are 15 device which are carried forward to the next month

Feb 2017: There are 200 eligible devices but actually only 160 got refreshed, plus 15 from Jan 15 so the total opening bal for Feb = 200 + 15 = 215 and then 160 to be deducted ie 55.

The same process will continue for all the other months and year.

The challenge:

Lets say by actual - eligible is named as Diff. This number should only take actual - eligible for the first month. from second month onward it should take actual - eligible and then the balance from previous month ie look up
How do i write a calc which only shows the calculation as described above for first month and then a look up + actual - eligible from previous month from next month onwards.

There would be month and year columns in filters, if i remove any year or month filter, the carry forward from that period will not be accounted for.

Answer 1

只要您正确设置分区和寻址，听起来Running_Sum([Diff])就可以解决问题。