Change of date between files with similar data

[ViniciusKimura]

I have a report that is pulled every day, and one of the fields of this report is the expected delivery date for each order of the report, what I want todo is compare 12 reports from different weeks and check how many dates were postponed and advanced between each one of the dates. I already achieved this with only two reports, but i dont have a clue of how to do with it with more reports.

Fields of the report:

DateOfReport

OrderNumber(dont change between reports)

Status (can change between reports)

DeliveryDate (th expected date of delivery. Can change between reports) 

the report has other fields, but is irrelevant.

Those reports are all storage in a folder, and the DateOfReport is added in PowerQuery using the origin file name, that have the date.

Can someone help me?

[lbendlin]

This is a standard pattern - use the Folder connector (or better, Sharepoint Folder) to list all the files you want to ingest and then run your comparisons either in Power Query or in DAX.  

Please provide sanitized sample data that fully covers your issue.

Please show the expected outcome based on the sample data you provided.