Selecting Rows of table, based on duplicate or not so select all unique rows or not,

This isn't a List.TransformMany solution but it something that should work too...

let
    atable = #table(
    type table [One = text, Two = text, Three = text],
    {
      {"a", "b", "c"},
      {"b", "c", "d"},
      {"c", "d", "e"},
      {"d", "e", "f"},
      {"b", "c", "d"},
      {"a", "b", "c"},
      {"e", "f", "g"}
    }
  ),
    select_same_rows = 
    Table.SelectRows(
      atable, 
      (r)=> 
      List.Count(
        List.PositionOf(
          Table.ToRows(atable),
          Record.FieldValues(r), 
          Occurrence.All
        )
      ) > 1
    )
in
    select_same_rows

Hi

let
  atable = Your_Table,
  ToRows = List.Buffer(Table.ToRows(atable)),
  Not_unique = List.Difference(ToRows, List.Distinct(ToRows)),
  Result = Table.SelectRows(
    atable,
    each List.Contains(Not_unique, Record.ToList(_)))
in
Result

Stéphane