Find MAX Value within a column

Hi powerlight1,

Create a new blank query. Open the advanced editor and paste in this code. You should be able to see what is happening in each step.

let
    Source = Table.FromRows(
        Json.Document(
            Binary.Decompress(
                Binary.FromText(
                    "i45WMrYwMDI3UNJRSkvMSykD0UWlmSXFQEZqGpAw0k1LLC5RitUhqNJYNzc1JbM0Vyk2FgA=", BinaryEncoding.Base64
                ),
                Compression.Deflate
            )
        ),
        let
            _t = ((type nullable text) meta [Serialized.Text = true])
        in
            type table [id = _t, category = _t, #"type" = _t, subtype = _t, sellingclass = _t]
    ),
    ct = Table.TransformColumnTypes(
        Source,
        {
            {"id", Int64.Type},
            {"category", type text},
            {"type", type text},
            {"subtype", type text},
            {"sellingclass", type text}
        }
    ),
    group = Table.Group(
        ct,
        {"id", "category", "type", "subtype"},
        {
            {"minsc", each List.Min([sellingclass]), type nullable text},
            {"maxsc", each List.Max([sellingclass]), type nullable text}
        }
    ),
    merge = Table.NestedJoin(
        ct,
        {"id", "category", "type", "subtype"},
        group,
        {"id", "category", "type", "subtype"},
        "group",
        JoinKind.LeftOuter
    ),
    expandrows = Table.ExpandTableColumn(merge, "group", {"minsc", "maxsc"}, {"minsc", "maxsc"})
in
    expandrows

The group step groups everything together and grabs the min and max values. You then merge with the CT step and the group step and expand the min-max columns. Power Query allows you to reference any step; it doesn't have to be the previous one.

Let me know if you have any questions.