Question : Substract time

Hi, I have got the form which runs the qry and returns the qry start time and end time.
The question is how I would find the difference between start and end in ms?
The code for the event to return time is included below as well as the screenshot of the form.

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             Private Sub cmd_runQry_Click()
On Error GoTo Err_cmd_runQry_Click
 
    Dim stDocName As String
 
    stDocName = "F1"
    
    'start time
    QryStart.Caption = Format(Now, "HH:nn:ss") & "." & Right(Format(Timer, "#0.000"), 3)
    DoCmd.OpenQuery stDocName, acNormal, acEdit
    'finish time
    QryFinish.Caption = Format(Now, "HH:nn:ss") & "." & Right(Format(Timer, "#0.000"), 3)
    
 
Exit_cmd_runQry_Click:
    Exit Sub
 
Err_cmd_runQry_Click:
    MsgBox Err.Description
    Resume Exit_cmd_runQry_Click
    
End Sub

           
         

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Answer : Substract time

You can use code like Cap1 suggested or you can use functions available withing access. Her are the functions you need:

TimeDif: Format([StartTime]-1-[EndTime],"Short Time")

The above will get the difference between the Start Time and End Time and you will get results like 04:10 (4 hours, 10 minutes), 01:30 (1 hour, 30 minutes).

HourMS: IIf(Left([TimeDif],2) Like ":",CInt(Left([TimeDif],1))3600000,CInt(Left([TimeDif],2))3600000)

The above converts the hour difference into integer and then into Milliseconds

MinuteMS: CInt(Right([TimeDif],2))*60000

The above converts the minutes difference into integer and then into Milliseconds

Total: [HourMS]+[MinuteMs]

The above is the total time difference in milliseconds

NOTE: YOU CAN ALWAYS COMBINE ALL THE FUNCTIONS ABOVE INTO ONE. I thought to separate the calculations so that you can see what is happening.