Sum time calculation in section footer of report

[DocBrown]

I have a report based on the following stripped down query.

SELECT Volunteers.VolunteerID, Volunteers.FirstName, Volunteers.SchoolName,
Int(CSng(nz(Sum([timeout]-[timein]),0)*24)) & ":" &
Format(Int(CSng(nz(Sum([timeout]-[timein]),0)*1440)) Mod 60,"00") AS
TotalHrs
FROM Volunteers LEFT JOIN VolunteerLog ON Volunteers.VolunteerID =
VolunteerLog.VolunteerID
GROUP BY Volunteers.VolunteerID, Volunteers.FirstName, Volunteers.SchoolName;

The report is grouped on SchoolName. The TotalHrs field is calculated from
the time logging [timeout] and [timein] fields in the VolunteerLog table. The
TotalHrs field is placed in the detail section of the report.

I would like to put a Sum total field in the section footer of the report.
How can I construct a calculation to do this?

Thanks,
John

 

[DocBrown]

Oops, this should be over in the Report section of this forum...