If I have a select like this:

SELECT SUM(DateDiff(Hour,Start,End)) AS Hour...

Will the Hour value obtained be as precise as this:

SELECT SUM(DateDiff(Second,Start,End)/3600) AS Hour...

Basically, the second one would provide a precision. So, Hour can end with something like 34.23.

I am wondering if the first one is having a precision for Hour if that DateDiff will be rounded to an integer such as 34.