max/min tow tables

[jbirco]

I have 2 fact tables 1 with old data and 1 with current data.
Can I write a max/min over a virtual column of both tables preserving the lineage to the original tables?

[Greg_Deckler]

@jbirco In theory yes but would need more information. Sorry, having trouble following, can you post sample data as text and expected output?
Not really enough information to go on, please first check if your issue is a common issue listed here: https://community.powerbi.com/t5/Community-Blog/Before-You-Post-Read-This/ba-p/1116882

Also, please see this post regarding How to Get Your Question Answered Quickly: https://community.powerbi.com/t5/Community-Blog/How-to-Get-Your-Question-Answered-Quickly/ba-p/38490

The most important parts are:
1. Sample data as text, use the table tool in the editing bar
2. Expected output from sample data
3. Explanation in words of how to get from 1. to 2.

[jbirco]

@Greg_Deckler 
Thanks for taking interest in my question
both tables have the same structure as copied below they are divided because they contain >100M rows
they are both related to a calender table
I want to run a measure for new customers
New Customers =
VAR firstsale =
CALCULATETABLE (
ADDCOLUMNS (
VALUES ( 'Sales' [CustID] ),
"firstsale", CALCULATE ( MIN ('Sales[Date]) )
),
ALL ( 'Calendar')
)
VAR firstsalenow =
FILTER ( firstsale, [firstsale] IN VALUES ('Sales'[Date]))
VAR result =
COUNTROWS ( firstsalenow )
RETURN
result
the question is if I can run it in a measure over both tables 

CustID	Date	ItemID	Amount	PaymentType