Fill missing sequence of rows

Hi, Anonymous 

I tried using your sample data. I got the required result. 

Refer to the ss

download the file that has the solution. 

https://file.io/tauFexFl0dsB

Hi Anonymous 

You can put the following code to advanced editor in power query

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("hZGxDsIwDET/JXMHxyYURsxcib2qqu5VF+D/KUOiGtnclAxPucu9cUwD5dSlx7psMxPzfr+/n6/bfmaiNHVfgiOiVEIigitxCghpRIE9zrBHHxDc3rgERGnEFfXIBAm4aQ43bT2Obwj0Iu4eEhHspdQeCu0rtK8mxXNrUzy3NsVzq9CtQremh+vWEuEef83Fm8rvb6cP", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Month = _t, Plan = _t, Customer = _t, Sales = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Month", type text}, {"Plan", type text}, {"Customer", type text}, {"Sales", Int64.Type}}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Changed Type", "Plan", Splitter.SplitTextByDelimiter("_", QuoteStyle.Csv), {"Plan.1", "Plan.2"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Plan.1", type text}, {"Plan.2", Int64.Type}}),
    #"Split Column by Position" = Table.SplitColumn(#"Changed Type1", "Month", Splitter.SplitTextByPositions({0, 1}, false), {"Month.1", "Month.2"}),
    #"Changed Type2" = Table.TransformColumnTypes(#"Split Column by Position",{{"Month.2", Int64.Type}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type2", "Custom", each if [Customer]="CustB" and [Plan.2]=2022 then List.Numbers(1,12) else if [Customer]="CustB" and [Plan.2]=2023 then List.Numbers(1,3) else null),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Month.1", "Month.2", "Plan.1", "Sales"}),
    #"Filtered Rows" = Table.SelectRows(#"Removed Columns", each ([Customer] = "CustB")),
    #"Removed Duplicates" = Table.Distinct(#"Filtered Rows", {"Plan.2", "Customer"}),
    #"Expanded Custom" = Table.ExpandListColumn(#"Removed Duplicates", "Custom"),
    #"Added Custom1" = Table.AddColumn(#"Expanded Custom", "Custom.1", each Table.SelectRows(#"Added Custom",(x)=>x[Plan.2]=[Plan.2] and x[Customer]=[Customer] and  x[Month.2]=[Custom])),
    #"Expanded Custom.1" = Table.ExpandTableColumn(#"Added Custom1", "Custom.1", {"Month.1", "Plan.1", "Sales"}, {"Month.1", "Plan.1", "Sales"}),
    #"Filled Down" = Table.FillDown(#"Expanded Custom.1",{"Month.1", "Plan.1"}),
    #"Reordered Columns" = Table.ReorderColumns(#"Filled Down",{"Plan.2", "Customer", "Month.1", "Custom", "Plan.1", "Sales"}),
    #"Merged Columns" = Table.CombineColumns(Table.TransformColumnTypes(#"Reordered Columns", {{"Custom", type text}}, "en-US"),{"Month.1", "Custom"},Combiner.CombineTextByDelimiter("", QuoteStyle.None),"Merged"),
    #"Reordered Columns1" = Table.ReorderColumns(#"Merged Columns",{"Customer", "Merged", "Plan.1", "Plan.2", "Sales"}),
    #"Merged Columns1" = Table.CombineColumns(Table.TransformColumnTypes(#"Reordered Columns1", {{"Plan.2", type text}}, "en-US"),{"Plan.1", "Plan.2"},Combiner.CombineTextByDelimiter("_", QuoteStyle.None),"Merged.1"),
    #"Renamed Columns" = Table.RenameColumns(#"Merged Columns1",{{"Merged", "Month"}, {"Merged.1", "Plan"}}),
    #"Reordered Columns2" = Table.ReorderColumns(#"Renamed Columns",{"Month", "Plan", "Customer", "Sales"}),
    #"Appended Query" = Table.Combine({#"Reordered Columns2", Table.SelectRows(#"Changed Type",(x)=>x[Customer]="CustA")})
in
    #"Appended Query"

Best Regards!

Yolo Zhu

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