I have a large monthly billing file dating back to January '15 - each row is a monthly billing record for a customer's product.
Example:
| Date | Customer Number | Product Number | Customer Duration | Product Duration |
| 10/1/2016 | 10050 | 100 | 17 | 12 |
| 9/1/2016 | 10050 | 100 | 16 | 11 |
| 8/1/2016 | 10050 | 100 | 15 | 10 |
| 7/1/2016 | 10050 | 100 | 14 | 9 |
| 6/1/2016 | 10050 | 100 | 13 | 8 |
| 5/1/2016 | 10050 | 100 | 12 | 7 |
| 4/1/2016 | 10050 | 100 | 11 | 6 |
| 3/1/2016 | 10050 | 100 | 10 | 5 |
| 2/1/2016 | 10050 | 100 | 9 | 4 |
| 1/1/2016 | 10050 | 100 | 8 | 3 |
| 12/1/2015 | 10050 | 100 | 7 | 2 |
| 11/1/2015 | 10050 | 100 | 6 | 1 |
| 10/1/2015 | 10050 | 200 | 5 | 5 |
| 9/1/2015 | 10050 | 200 | 4 | 4 |
| 8/1/2015 | 10050 | 200 | 3 | 3 |
| 7/1/2015 | 10050 | 200 | 2 | 2 |
| 6/1/2015 | 10050 | 200 | 1 | 1 |
I filled out the two columns I want to create a measure for (Customer Duration & Product Duration). The file has thousands of different customers so that will need to be the lookup value I suppose, but how do I account for the time factor? I've linked a calendar table's Date Key to the Date in the above table if that helps.
Thanks!