Help!! Creating a column with the "running" count

Assuming that you are trying to form group , please try usng Group option OOTB from Power BI . If you are looking for specific scenario , can you share some relationship on the type of relation you are seeking .

Regards,

Jupsimar Singh.

Mark my post as a solution if it helped you !

Hello, Z_PowerBi try this approach

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W8nR3UorViVZydXEG08Euzk6oDJgKMB0LAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Board = _t]),
    lst = List.Buffer(Source[Board]),
    count = List.Count(lst),
    id_column =  
        List.Generate(
            () => [i = 1, board = lst{0}, value = 1],
            (x) => x[i] <= count,
            (x) => [i = x[i] + 1, board = lst{x[i]}, value = if x[board] <> lst{x[i]} then x[value] else x[value] + 1],
            (x) => {x[board], x[value]}
        ),
    to_tbl = Table.FromRows(id_column, {"Board", "ID"})
in
    to_tbl