Calculate time between time-stamp entries based on row conditions

Hi bocajpedersen ,

Here's my approach 

1. Add a column subtracting Out - In , as duration.

2. Add a column extracting either date ( assuming both are always the same)

3. Group by person Id and date, aggregation is sum of the duration. ( This should be on site time)

4. Could negate 24 hours from this to get offsite time

If this doesn't resolve the issue , Kindly post the raw data in a table/ readable query format with any other considerations while masking sensitive data.

Thanks for the quick response. 

I am trying to calculate the time from swiping off, and then returning to site to swipe back on - not just 24-onsite_time. 

Hi bocajpedersen, I know that this topic is few months old, but if you have big dataset - consider using this query (this one is much faster)

Result

let
    fnShift = (tbl as table, col as text, shift as nullable number, optional newColName as text, optional _type as type) as table =>
        //v 3. parametri zadaj zaporne cislo ak chces posunut riadky hore, kladne ak dole, 4. je nepovinny (novy nazov stlpca), 5. je nepovinny typ
        let
            a = Table.Column(tbl, col),
            b = if shift = 0 or shift = null then a else if shift > 0
                then List.Repeat({null}, shift) & List.RemoveLastN(a, shift)
                else List.RemoveFirstN(a, shift * -1) & List.Repeat({null}, shift * -1),    
            c = Table.FromColumns(Table.ToColumns(tbl) & {b}, Table.ColumnNames(tbl) &
                ( if newColName <> null then {newColName} else
                    if shift = 0 then {col & "_Duplicate"} else
                    if shift > 0 then {col & "_PrevValue"} 
                    else              {col & "_NextValue"} )),
            d = Table.TransformColumnTypes(c, {List.Last(Table.ColumnNames(c)), if _type <> null then _type else type any})
        in
            d,

    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("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", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Person ID" = _t, #"Date/Time In" = _t, #"Date/Time Out" = _t]),
    Custom1 = if UseRepeatValue = "Yes" then Table.Repeat(Source, RepeatValue) else Source,
    ChangedType = Table.TransformColumnTypes(Custom1,{{"Person ID", type text}, {"Date/Time In", type datetime}, {"Date/Time Out", type datetime}}),
    Ad_DateIn = Table.AddColumn(ChangedType, "Date In", each DateTime.Date([#"Date/Time In"]), type date),
    Ad_DateOut = Table.AddColumn(Ad_DateIn, "Date Out", each DateTime.Date([#"Date/Time Out"]), type date),
    // Added [Date/Time Out_PrevValue] into inner [All] table
    GroupedRows = Table.Group(Ad_DateOut, {"Person ID", "Date In", "Date Out"}, {{"All", each fnShift(_, "Date/Time Out", 1, null, type datetime), type table}}),
    CombinedAll = Table.Combine(GroupedRows[All]),
    Ad_TimeSincePreviousEntray = Table.AddColumn(CombinedAll, "Time Since Previous Entry", each [#"Date/Time In"] - [#"Date/Time Out_PrevValue"], type duration),
    RemovedColumns = Table.RemoveColumns(Ad_TimeSincePreviousEntray,{"Date/Time Out_PrevValue", "Date In", "Date Out"})
in
    RemovedColumns