Start - Stop

[Leeus]

I have a SQL db that logs when a user dials in to our dial in account and then again stops the connection.
It logs the start time, and allocates a field with "Start" and one with "Stop" and a stop time when it finishes.

At the moment I have a query that looks at all of the events in a day, adds all the stops together, then all the starts and takes the difference, hopefully giving the cumulative time online for that one day! Problem I have is that some users stay online overnight so it throws my readings out.
Now to my question, is there a way of saying that if a username starts he day with a stop event to ignore that entry, likewise, end the day with a start.

Thanks all for your help.

 

[Yesca]

These examples return number of minutes between the start and stop time. If you want to ignore the midnights, use:

select [start], [stop], (([stop] - [start]) * 1440) as [diff] from [time check] where [start] < [stop]

but to get all values, including midnight-crossers:

select [start], [stop], ((([stop] - [start]) * 1440) + iif([start] > [stop],1440,0)) as [diff] from [time check]