Hi @ells,
Okay see if this performs better than the Merge
In the Sales table query (in the advanced editor) create a new variable, something like:
ListCountries = List.Buffer(Country[Country])
Next create a filter step in Sales through the UI and change the M code in the formula bar to:
Table.SelectRows(#“You Prev Step Name”, each (List.Contains(ListCountries ,[Country])=true ))
I hope this is helpful.