Append Column to rows derived from the from two columns

Hi jwb3d 

Will the phase column always contain the list of characters to append to deviceName concatenated as a string?

If so, I would consider a query similar to the example below (Source step hard-coded to illustrate):

let
  Source = #table(
    type table [
      fid         = Int64.Type,
      phaseCount  = Int64.Type,
      phase       = text,
      extractDate = date,
      deviceName  = text
    ],
    {
      {201800722, 3, "ABC", #date(2026, 3, 3), "Device1"},
      {821047293, 2, "AC", #date(2026, 3, 3), "Device10"},
      {720183650, 1, "D", #date(2026, 3, 3), "Device9"}
    }
  ),
  #"Add deviceNamePhase" = Table.AddColumn(
    Source,
    "deviceNamePhase",
    each List.Transform(Text.ToList([phase]), (phaseChar) => [deviceName] & phaseChar),
    type {text}
  ),
  #"Expand deviceNamePhase" = Table.ExpandListColumn(#"Add deviceNamePhase", "deviceNamePhase"),
  #"Add Index" = Table.AddIndexColumn(#"Expand deviceNamePhase", "Index", 1, 1, Int64.Type)
in
  #"Add Index"

Would something like this work for you?