SQL Date Diff between Upload time 1 and 2 - sql

Question

I'm new to SQL and was wondering if you could help me create a query that compares the time difference in Days, Hours, Minutes.
For example,
Start time 1 = 13/01/2016, 16:00
End time 1 = 14/01/2016, 18:00
So the time difference should be 1 day and 2 hours right?
Another example.
Start time 2 = 20/10/2016, 12:00
End time 2 = 20/10/2016, 16:00
So the
time difference is just 2 hours.
The reason I need this query is to create a report based on the difference in time between a start time and a finish time of a task.

Answer 1

watch out for problems with DATEDIFF that ignores fractions of days etc
DECLARE #Starttime DATETIME = '20160113 16:00';
DECLARE #Endtime DATETIME ='20160114 15:59';
--calculate difference in seconds then use integer divides and MODULUS to extract days, hours, minutes
;WITH DIFF_SECS AS (SELECT CAST(DATEDIFF(second,#Starttime,#Endtime) AS BIGINT) AS SD)
SELECT SD / (24 * 3600) as NoDays,
(SD % (24 * 3600)) / 3600 as NoHours,
(SD % 3600) / 60 AS NoMinutes
FROM DIFF_SECS;
if you aren't using microsoft SQL - then the formulae are possible still useful
if X = 'difference between times in seconds'
then whole days = X / (24 * 3600) where the divide is an integer divide (always rounds down)

Answer 2

In Oracle I would do it like that:
-- this is only to create some data
WITH MyRows AS (
SELECT to_date('2000/11/30 12:59', 'YYYY/MM/DD HH24:MI') BEGINNING, to_date('2000/11/30 14:01', 'YYYY/MM/DD HH24:MI') ENDING FROM DUAL UNION
SELECT to_date('2000/12/01 12:59', 'YYYY/MM/DD HH24:MI') , to_date('2000/12/02 00:01', 'YYYY/MM/DD HH24:MI') FROM DUAL UNION
SELECT to_date('2000/12/30 12:59', 'YYYY/MM/DD HH24:MI') , to_date('2000/12/31 14:01', 'YYYY/MM/DD HH24:MI') FROM DUAL UNION
SELECT to_date('2000/12/31 12:59', 'YYYY/MM/DD HH24:MI') , to_date('2001/01/01 04:01', 'YYYY/MM/DD HH24:MI') FROM DUAL
)
-- this is the select
SELECT
BEGINNING,
ENDING,
ENDING-BEGINNING IN_DAYS,
(ENDING-BEGINNING)*24 IN_HOURS,
(ENDING-BEGINNING)*24*3600 IN_SECONDS,
case
when (ENDING-BEGINNING)*24*60 >= 3 then round(((ENDING-BEGINNING)*24*60-3)*2)
else 0
end Total_cost_in_hamburgers
FROM MyRows
;
timedifferences are days and if you want to calculate with it (f.e. after 3 minutes every minute costs 2 hamburgers) it is better to calculate that way