How do I return a list of products that have not occured within the last 6 months?

[mcash]

I have a giant table that includes a SalesDate column, a ProductID column, a ProductName column, and other colums containing customer and sales data. I want to list only the ProductNames that have not been sold in the last 180 days. I tried the following DAX to create a table, but I am finding transactions on that list that have occured in the last 180 days. I only want to see products that haven't sold in the past 180 days for product management.

= FILTER(SUMMARIZE(Sales, Sales[ProductID], "LastSaleDate", MAX(Sales[SaleDate])),
         [LastSaleDate] < TODAY() - 180 || ISBLANK([LastSaleDate]))

How can I accomplish this?

[amitchandak]

@mcash , You have to consider the lost customer approach

Rolling 6 = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date],MAX('Date'[Date]),-6,MONTH))

Not Sold in last 6= countx(Product[Product]), if(Isblank([Rolling 6]), [Product], blank())

LTD Vs Period Retention
https://community.powerbi.com/t5/Community-Blog/Customer-Retention-Part-5-LTD-and-PeriodYoY-Retentio...

Customer Retention with Dynamic Segmentation, New/Lost/Retain Customer Count: https://youtu.be/EyL7KMw877Q