Trying to create a new column based on the query or source file name.

Hi dmarics28 ,

Try to change the code of your Append query in the Advanced Editor.

let
    Source = Table.Combine({Table.AddColumn(#"query A", "source query", each "query A")
                            , Table.AddColumn(#"query B", "source query", each "query B")
                            , Table.AddColumn(#"query C", "source query", each "query C")})
in
    Source

BTW, .pbix file attached.

Best Regards,

Icey

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.