Find row with latest date and keep one

Hello PowerBeeEye 

the easiest and shortest way to do is to put all what you needed in the Group-function and expand it later

here the code snipped for the function of the group function (you can substitute with your function, and it will work). No need to create an additional column to extract etc.

        {
            {
                "PickUpLatest", 
                (tbl)=> Table.FirstN(Table.SelectRows(tbl, (row)=> row[Scan Date]= List.Max(tbl[Scan Date])),1)
            }
        }

here a complete code example to see how the above function is working

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjIwMtA1sNQ1NFXSUXJLTCrKzE7M1UvOzwVyFZRidRAqDEAqnPPzSvKL87EqMCRPQSwA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Scan Date" = _t, ForestDNSName = _t, Column1 = _t]),
    ChangeType = Table.TransformColumnTypes(Source,{{"Scan Date", type date, "en-US"}, {"ForestDNSName", type text}, {"Column1", type text}}),
    GroupAndPickUpLatest = Table.Group
    (
        ChangeType, 
        {"ForestDNSName"}, 
        {
            {
                "PickUpLatest", 
                (tbl)=> Table.FirstN(Table.SelectRows(tbl, (row)=> row[Scan Date]= List.Max(tbl[Scan Date])),1)
            }
        }
    ),
    PickUpLatest = Table.ExpandTableColumn(GroupAndPickUpLatest, "PickUpLatest", {"Scan Date", "Column1"}, {"Scan Date", "Column1"})
in
    PickUpLatest

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

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Kudoes are nice too

Have fun

Jimmy