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Average Time between records

rbuserrbuser
edited September 2001 in General
I have a field 'recordDateTime' in my DB table. On a report's summary
band, I would like to show a value "average time between postings".

For example, if my DB had the following records:

recordDateTime
--------------
9/2/2001 4:00:00 pm
9/2/2001 4:10:00 pm
9/2/2001 4:20:00 pm

I would like the summary band to be able to read "10 minutes", although
it doesn't matter what format (I'd be willing to do conversion via
code.) It doesn't look like I can use a DBCalc component.

Can anyone help?

Thanks.

Comments

  • rbuserrbuser
    edited September 2001
    Hi,

    try something like:

    For the report use a query which sorts on your posting date.
    Create a TList (MeanList) with the report.
    Define a TObject (Timepart) which contains two doubles.
    Use a ppVariable to show the date. Within the onCalc event of the
    ppVariable create a new TObject (Timepart), set the first double with
    the current datetime and put the TObject into the TList (MeanList).

    Within the beforegenerate event of the summary band compute your mean.

    Get the first datetime. Store it into a variable. Set the second double
    to zero.
    Go to the next list item. Subtract the variable from the current
    datetime. Store the result into the second double. Store current
    datetime to variable.
    Repeat till list end.
    Build summary of all second datetimes (Beware a datetime integral part
    are the days and the fraction shows the hours, minutes and seconds of a
    day. Therefore build a sum of minutes: integral part * 1440 and add the
    hours * 60 and minutes you got by a DecodeTime(,,,,)).
    Divide sum by Listcount.
    Mean done.

    Show the mean via a ppLabel.
    Free the TObjects within the TList.
    Free the TList.

    enjoy,
    Ron.

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