I wonder if anyone can help me.

I have designed a report and the only reference to time spent is captured from the date & time stamp log. So I have tracked someone logging an activity as follows on the table custom_log.DateCreated.

14.53.02 11/10/2012
14.53.06 11/10.2012
14.53.17 11/10/2012
14.53.54 11/10/2012
14.53.54 11/10/2012

What I need to work out is how to calculate the difference in time when they first logged something at 14.53.02 and when they finished at 14.53.54

If anyone can point me in the right direction that will be brilliant. Thanks

Steve

Also You can Try,
Convert your field to String, if not, then:
Create Formula Formula1 : DateTime (YYYY, MM, DD, HH, MM, SS)
In your case:
DateTime ( ToNumber (right ({@FIELD},4)),
           ToNumber (Mid ({@FIELD},13,2)),
           ToNumber (Mid ({@FIELD},10,2)),
           ToNumber (LEFT ({@FIELD},2)),
           ToNumber (Mid ({@FIELD},4,2)),
           ToNumber (Mid ({@FIELD},7,2)) )

Then use lockwelle's Formula :
DateDiff ("s",maximum({@Formula1}), minimum({@Formula1})) / 3600;

thank so much for your reply but I have to be honest, this blew my sock off and went over me head.

I have achieved much with datediff("s", {custom_Log.DateCreated}, next({custom_Log.DateCreated})) but now I want to now how to convert seconds into "m" & "s" so if you can help me with that I will be most grateful.

Regards,

Steve