Format date directly in the function

= Table.AddColumn(#"Changed Type", "Start of Month", each Date.From(Text.From([yyyymm])&"01"), type date)

Hi Spigaw ,

Based on your M synatx, It seemed that the data type has changed from text to Number firstly by default ,which is not necessary.

So please delete the Changed type step in order to simplify your code and then use the following synatx in the Advanced Editor:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjIwMrBUitWBsAwNlGJjAQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Test = _t]),
    #"Added Custom" =Table.TransformColumnTypes( Table.AddColumn(Source, "Custom", each Date.From(#date(Number.FromText(Text.Start([Test],4)),Number.FromText(Text.End([Test],2)),1))   ),{{"Custom", type date}})
   in
    #"Added Custom"

Best Regards,
Eyelyn Qin
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