Duration between two dates.

Hi,

This M code works

let
    Source = Excel.CurrentWorkbook(){[Name="Data"]}[Content],
    #"Removed Columns" = Table.RemoveColumns(Source,{"ids"}),
    #"Grouped Rows" = Table.Group(#"Removed Columns", {"car", "user", "event"}, {{"All", each Table.AddIndexColumn(_,"Index",1,1)}}),
    #"Expanded All" = Table.ExpandTableColumn(#"Grouped Rows", "All", {"date_time", "Index"}, {"date_time", "Index"}),
    #"Merged Columns" = Table.CombineColumns(Table.TransformColumnTypes(#"Expanded All", {{"car", type text}, {"Index", type text}}, "en-IN"),{"car", "user", "Index"},Combiner.CombineTextByDelimiter(";", QuoteStyle.None),"Merged"),
    #"Pivoted Column" = Table.Pivot(#"Merged Columns", List.Distinct(#"Merged Columns"[event]), "event", "date_time"),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Pivoted Column", "Merged", Splitter.SplitTextByDelimiter(";", QuoteStyle.Csv), {"Car", "User"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Car", Int64.Type}, {"User", type text}, {"KeyOut", type datetime}, {"KeyIn", type datetime}}),
    #"Added Custom1" = Table.AddColumn(#"Changed Type", "Current time", each DateTime.LocalNow() as datetime),
    #"Added Custom" = Table.AddColumn(#"Added Custom1", "Duration", each if [KeyIn]=null then [Current time] - [KeyOut] else [KeyIn]-[KeyOut]),
    #"Changed Type1" = Table.TransformColumnTypes(#"Added Custom",{{"Duration", type duration}})
in
    #"Changed Type1"