Different Date Time Calculation steps in Apex.
"Best way to find the difference b/w two date time fields
//************************************************
Datetime startDate = system.now();// Start date
Datetime endDate = system.now().addHours(60);//End Date
integer intDays = startDate.Date().daysBetween(endDate.Date());
datetime sameDayEndDate = startDate.addDays(intDays);
decimal decHours = ((endDate.getTime())/1000/60/60) - ((sameDayEndDate.getTime())/1000/60/60);
//************************************************
intDays : this value show the number of day b/w the given datetime (2 days for the given dates)
decHours : this value shows the number of (12 hours for the given dates )
so total diff is : 2 days and 12 hours
************************************************
If you want to find the diff in days and minutes than modify the foumula accordingly
for minutes :
decimal decMinutes = ((endDate.getTime())/1000/60) - ((sameDayEndDate.getTime())/1000/60);
So total diff is : 2 days and 720 minutes for the given dates .
so you can find the difference in whatever the format you want."
