Update Historical Table with Daily Data in Power Query

Hi Anonymous ,

You could refer to below M code yo see whether it work or not.

let
    Source = Table.NestedJoin(history, {"id"}, daily, {"id"}, "daily", JoinKind.LeftOuter),
    #"Expanded daily" = Table.ExpandTableColumn(Source, "daily", {"price", "view"}, {"daily.price", "daily.view"}),
    Custom1 = Table.ReplaceValue(#"Expanded daily",each [price], each if [price]=[daily.price] or [daily.price]=null then [price] else [daily.price], Replacer.ReplaceValue, {"price"}),
    Custom2 = Table.ReplaceValue(#"Custom1",each [view], each if [view]=[daily.view] or [daily.view]=null then [view] else [daily.view], Replacer.ReplaceValue, {"view"}),
    Custom3 = Table.ReplaceValue(#"Expanded daily",each [daily.view], each if [view]=[daily.view] and [price]=[daily.price] or [daily.view]=null then null else DateTime.LocalNow(), Replacer.ReplaceValue, {"daily.view"}),
    #"Removed Columns" = Table.RemoveColumns(Custom3,{"daily.price"})
in
    #"Removed Columns"

 In addition, if the date column in daily table, you could change code like below(you also need to exapnd this column in table)

Custom3 = Table.ReplaceValue(#"Expanded daily",each [daily.view], each if [view]=[daily.view] and [price]=[daily.price] or [daily.view]=null then null else [daily.date], Replacer.ReplaceValue, {"daily.view"})

Best Regards,
Zoe Zhi

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