Removing duplicates using running index number?

Here's one way to do it in the query editor, with a GroupBy and the Table.Max function.  To see how it works, just create a blank query, open the Advanced Editor and replace the text there with the M code below.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjQwMFTSUTLUN9I3MjAyBjIdlWJ1kMQNYeJOqOLGMHFnmLgRkGOEUI8iboxDHMl8oL2xAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [SKU = _t, #"Delivery Date" = _t, Other = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"SKU", Int64.Type}, {"Delivery Date", type date}, {"Other", type text}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"SKU"}, {{"AllRows", each _, type table [SKU=nullable number, Delivery Date=nullable date, Other=nullable text]}}),
    Custom1 = Table.TransformColumns(#"Grouped Rows", {{"AllRows", each Table.Max(_, "Delivery Date")}}),
    #"Expanded AllRows" = Table.ExpandRecordColumn(Custom1, "AllRows", {"Delivery Date", "Other"}, {"Delivery Date", "Other"})
in
    #"Expanded AllRows"

Pat