From: Jan Steinman
Date: October 1 2011 3:08am
Subject: Quantity of time from difference of two Datetime values?
List-Archive: http://lists.mysql.com/mysql/225875
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Okay, I've reviewed the online man page for date and time functions, and =
I've played with several likely candidates, and I am still having =
trouble subtracting two arbitrary Datetimes to get something that is =
useful. A simple subtraction yields the least useful thing possible: a =
modulo-100 difference of modulo-60 quantities. Other functions yield the =
proper answer, but not for a quantity of time that rolls over midnight, =
etc.

Surely, there are tons of payroll apps that subtract the punch-out from =
the punch-in to come up with a quantity of time?

What is YOUR favourite way of coming up with a quantity of time as the =
difference between two arbitrary Datetimes? Did I overlook something =
simple? Do I need to convert the two to scalar integers first?