Flatten Parent Child Hierarchy

Hello, androo 

let
    Source = your_table,
    f = (tbl as table) =>
        [count = Table.RowCount(tbl),
        lst = List.Buffer(List.Transform({1..count}, Text.From)),
        ids = Record.FromList(tbl[C_ID], List.Transform(lst, (x) => "C_ID_" & x)),
        names = Record.FromList(tbl[C_Name], List.Transform(lst, (x) => "C_Name_" & x)),
        res = [id = ids, name = names]][res],
    g = Table.Group(Source, {"P_ID", "P_Name"}, {{"all", f}}),
    expand = Table.ExpandRecordColumn(g, "all", {"id", "name"}),
    id_cols = List.Distinct(List.Combine(List.Transform(expand[id], Record.FieldNames))),
    name_cols = List.Distinct(List.Combine(List.Transform(expand[name], Record.FieldNames))),
    expand_id = Table.ExpandRecordColumn(expand, "id", id_cols),
    expand_name = Table.ExpandRecordColumn(expand_id, "name", name_cols)
in
    expand_name