Data reduction in dimension tables

If these are from the same database, a mere inner join from dimension to fact would normally be your best option (without the buffer, which causes the problem you describe above.

You could also try a buffered list instead of table, by making a query that gets the distinct values from the customer column of the fact table, like List.Distinct(Fact[Customer])

Name that query FilterValues.

Now when you make your fact table query, filter like:

Table.SelectRows(PriorStepOrTableName, each List.Contains(List.Buffer(FilterValues), [CustomerColumnNameFromThisFactTable]))

--Nate

Try using a buffered list instead of a buffered table:

Table.SelectRowsFactTabls