All date/time fields are really just Double (floating point) values. Only the dispaly is different. The "Integer" portion of the value represents the number of "Days" since the starting point (Dec 30, 1899?). the "decimal" Fractional portion represents the part of the day simce midnight. So a date/time of:
0.5 = 12 hours;
1 hour = 0.083333 days;
1/2 half hour (30 Minutes = 0.04166667 days);
1 Minute = 1.38888888888889E-03 days
1 Second = 2.31481481481482E-05 days
Thus, properly calculated time intervals work perfectly well with the sum function in a query.
For example:
A table:
MyIndex RaceTime
1 1:00
2 1:22
3 3:26
4 2:12
5 1:06
6 1:23
[/b]
A Query:
SELECT Sum(RaceTime_2.RaceTime) AS SumOfRaceTime
FROM RaceTime_2;
A Query Results:
SumOfRaceTime
0.439016203703704
The same query Results with the Format changed to Short time
SumOfRaceTime
10:32
Note that the Table "times" are properly formatted as short time. If your times are as text, some odditites/errors may occur. When the query is 'built', if you do not force the field format to 'short time', you get the fraction of a day - not the time.
I do not understand what you are doing in any detail, so cna only offer this brief example / explination. Summing intervals in MS Access is VALID and commonly done. My only comment is / was toward the tabel design, which causes extra work to chieve a realtively simplistic goal, as you need two interval calculations per record - and then need to sum them within the record. A design which simply included TimeIn and TimeOut could produce the same report with only one 'record' calculation (TimeOut - TimeIn), with the summation in the query alone. Since you need to group by employee anyway, the results are the same. 'Modern' relational database design favors "deep" (many records with less info) over "wide" fewer records but more fields (info) per record. Your design limits the excursions of an employee to two per day, while the more general approach allows as many as necessary. While this may appear to be a trivial issue, it is a design thought/approach/technique which will cause problems. If not in the here and now - certainly in the future.
MichaelRed
mred@att.net
There is never time to do it right but there is always time to do it over