Вы можете использовать этот скрипт PowerQuery:
let
Source = Excel.Workbook(File.Contents("Dates.xlsx"), null, true),
Sheet1_Sheet = Source{[Item="Sheet1",Kind="Sheet"]}[Data],
#"Changed Type" = Table.TransformColumnTypes(Sheet1_Sheet,{{"Column1", type text}}),
#"Split Column by Delimiter" = Table.SplitColumn(#"Changed Type", "Column1", Splitter.SplitTextByDelimiter(" ", QuoteStyle.Csv), {"Column1.1", "Column1.2", "Column1.3"}),
#"Added Month" = Table.AddColumn(#"Split Column by Delimiter", "Month", each if [Column1.1] = "January" then 1 else if [Column1.1] = "February" then 2 else if [Column1.1] = "March" then 3 else if [Column1.1] = "April" then 4 else if [Column1.1] = "May" then 5 else if [Column1.1] = "June" then 6 else if [Column1.1] = "July" then 7 else if [Column1.1] = "August" then 8 else if [Column1.1] = "September" then 9 else if [Column1.1] = "October" then 10 else if [Column1.1] = "November" then 11 else if [Column1.1] = "December" then 12 else 0),
#"Added Day" = Table.AddColumn(#"Added Month", "Day", each Text.Select([Column1.2], {"0".."9"})),
#"Removed Columns" = Table.RemoveColumns(#"Added Day",{"Column1.1", "Column1.2"}),
#"Renamed Columns" = Table.RenameColumns(#"Removed Columns",{{"Column1.3", "Year"}}),
#"Changed Type2" = Table.TransformColumnTypes(#"Renamed Columns",{{"Year", Int64.Type}, {"Month", Int64.Type}, {"Day", Int64.Type}}),
#"Inserted Merged Column" = Table.AddColumn(#"Changed Type2", "Date", each Text.Combine({Text.From([Day], "de-DE"), "/", Text.From([Month], "de-DE"), "/", Text.From([Year], "de-DE")}), type text),
#"Changed Type3" = Table.TransformColumnTypes(#"Inserted Merged Column",{{"Date", type date}}),
#"Removed Columns2" = Table.RemoveColumns(#"Changed Type3",{"Year", "Month", "Day"})
in
#"Removed Columns2"
Преобразование в окончательный формат данных зависит от ваших локальных настроек и обычно выполняется вне PowerQuery.