Business process start at time B, for example, 2009-12-08 10:48:11 and ended at time A, for example, 2009-12-08 10:49:53.
I have to calculate "time A-time B" and want a result in format hh:mi:ss.
Unfortunately, time A - time B is of type float, and typically is sth like
Result of DATE subtraction is "number of days". Now that you know that "time A - time B" gives days, it is a matter of calculation to transform it into any format you want (1 day = 24 hours, 1 hour = 60 minutes, 1 minute = 60 seconds, ...).