No it'll not be precise. It's literally difference between hours in both dates w/o any respect to Minutes, seconds, milliseconds

>If I have a select like this:
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>

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

>
>Will the Hour value obtained be as precise as this:
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>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.