Need help with creating week number / week sequence number

Hello Anonymous 

sure it's possible. Everything is possible with Power Query 🙂

See this example

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjE2tTDTMTVQitUBcczMLXSMTKEcc3MDHVMEx1LH2BjKsTA00bEA6okFAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Date = _t]),
    ChangeNumberToDate = Table.TransformColumns(Source,{{"Date", each DateTime.From(Number.From(_)), type datetime}}),
    AddedCustomColumn = Table.AddColumn(ChangeNumberToDate, "Week of month", each Date.WeekOfYear
        (
            [Date]
        )
        -
        Date.WeekOfYear
        (
            #date
            (
                Date.Year([Date]),
                Date.Month([Date]),
                1
            )
        )
        +1)
in
    AddedCustomColumn

Copy paste this code to the advanced editor to see how the solution works

If this post helps or solves your problem, please mark it as solution.
Kudos are nice to - thanks
Have fun

Jimmy