Tælle dage pr. måned mellem to datoer

Use the datediff function for doing this

sådan bruger du datediff
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/script56/html/vsfctDateDiff.asp

DateDiff("d", [Startdato], [Slutdato]) will give you how many days there are for the whole period
to do this for each month would involve some programming as it will be very likley that the period will change and therefore the number of months/days will change.
It also depend on HOW you want to see the result

Jeg ønsker at få et antal dage pr. måned f.eks i et sygedageregnskab hvor en person er syg i en periode ud over en kalendermåned - men dagene/timerne skal tælles pr. måned.

pecl>This IS going to take some programming so if you dont know much about that then I think you have some problmes!
How the code(VBA) is depends on HOW you want to see this information!

It isnt simple to extract each month from the date interval, but when that is done the datediff function can calculate the number of days in each month.
Access has some very good date functions so I suggest you take a look at those.

Prøv med følgende funktion

Function DaysInMonth(StartDate As Date, EndDate As Date, Month As Integer) As Integer

Dim RunningDate As Long
DaysInMonth = 0
If EndDate > StartDate Then
    RunningDate = StartDate
    Do While RunningDate <= EndDate
        If DatePart("m", RunningDate) = Month Then
            DaysInMonth = DaysInMonth + 1
        End If
        RunningDate = RunningDate + 1
    Loop
End If

End Function

Hej Superjap
Hvordan får jeg vist resultatet (dage pr. måned) - så jeg kan arbejde videre med det ?

I et felt på en formular skriver du blot

=DaysInMonth([Start];[Slut];[Måned])

Start, SLut og Måned er så andre felter på formularen.

Superjap> Jeg får det ikke til at virke. Kan du sende et eksempel til mig ? Min mail er per.clemensen@hvalsoe.dk

Den er på vej.

Superjap> Tak for hjælpen - det virker fint.
Du får de 30 point.

Tak for det.