I assume you need to count the users in the predefined time intervals.
Time Interval #Users
For doing this you need to create a mapping table which will create different intervals and then load the data on the basis of these intervals.
Please refer to "IntervalMatch" Load functionality provided by Qlikview.
You can also use loop and group by to get number of concurrent sessions
1 as Counter,
[Session Start] + IterNo()/24/60-(1/24/60) as TimestampTemp
While [Session Start] + IterNo()/24/60-(1/24/60) <= Timestamp;
Date(TimestampTemp, 'YYYYMMDD') &'_'& Hour(TimestampTemp)&'_'& Minute(TimestampTemp) as DateMinuteKey,
SUM(Counter) as SessionsCounter
GROUP BY Date(TimestampTemp, 'YYYYMMDD') &'_'& Hour(TimestampTemp)&'_'& Minute(TimestampTemp);
Use DateMinuteKey for linking into Calendar table.