Power Query Do While Loop

Hi,

I am trying to replicate a SQL do while loop.

I have a table with customers some are active some are inactive and I need to get the figures for each month end using the created and terminated dates.

In SQL I would set up a loop to do my calculation and add one month to the date in the loop to add the data to a temp table.

E.G. the example code would be if Customer was created prior to the month end and the termonation date is blank or greater than  the month they where active at the month end so include in the new table.

I have am having difficulty setting this up in Power Query so that the data from the data from the customer table is added to a new table and with each loop the next months data is appended to the table and so on  until teh max date is reached (the previous month end date).

I have looked at many eaxmples and they dont seem to do what I Need, if it can be done 

Any help would be greatly appreciated