Adding new rows to a table based on previousday value

Hi, Anonymous ;

You could duplicate a table as TableB, then grroup by the min date , and add yestoday date column.

Then merge column from original table and TableB,

Last sort and fill down.

See the working here - Open a blank query - Home - Advanced Editor - Remove everything from there and paste the below code to test.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("dc9JCsAgDAXQqxTXgeqPqelZxEV7/0N0ULB1CGQRePwkMRpnyBx3L7k28sz3qKvTFRYwiTI6K3KkwQ/R8UUs+iKgIrQIsnVJ+K9jsmIz2qc3lbzswNOznvIBHUP7IusYNVlOCpPC0gU=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [userid = _t, productid = _t, value = _t, date = _t]),
    #"Grouped Rows" = Table.Group(Source, {"userid", "productid"}, { {"min", each List.Min([date]), type nullable text}}),
    #"Added Custom" = Table.AddColumn(#"Grouped Rows", "max", each Date.From( DateTime.LocalNow())-#duration(1,0,0,0)),
    #"Reordered Columns" = Table.ReorderColumns(#"Added Custom",{"userid", "productid", "min", "max"}),
    #"Changed Type with Locale" = Table.TransformColumnTypes(#"Reordered Columns", {{"min", type date}, {"max", type date}}, "en-US"),
    Custom1 = Table.AddColumn(#"Changed Type with Locale", "date", each {Number.From([min])..Number.From([max])}
),
    #"Expanded Custom" = Table.ExpandListColumn(Custom1, "date"),
    #"Changed Type" = Table.TransformColumnTypes(#"Expanded Custom",{{"date", type date}}),
    #"Removed Columns" = Table.RemoveColumns(#"Changed Type",{"min", "max"}),
    #"Merged Queries" = Table.NestedJoin(#"Removed Columns", {"userid", "productid", "date"}, Table, {"userid", "productid", "date"}, "Table", JoinKind.LeftOuter),
    #"Expanded Table" = Table.ExpandTableColumn(#"Merged Queries", "Table", {"value"}, {"Table.value"}),
    #"Sorted Rows" = Table.Sort(#"Expanded Table",{{"userid", Order.Ascending}, {"productid", Order.Ascending}, {"date", Order.Ascending}}),
    #"Filled Down" = Table.FillDown(#"Sorted Rows",{"Table.value"})
in
    #"Filled Down"

Best Regards,
Community Support Team _ Yalan Wu
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