From: Hank
Date: October 1 2011 3:22am
Subject: Re: Quantity of time from difference of two Datetime values?
List-Archive: http://lists.mysql.com/mysql/225876
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n Fri, Sep 30, 2011 at 11:08 PM, Jan Steinman wrote:
> 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 s=
ubtracting two arbitrary Datetimes to get something that is useful. A simpl=
e subtraction yields the least useful thing possible: a modulo-100 differen=
ce of modulo-60 quantities. Other functions yield the proper answer, but no=
t for a quantity of time that rolls over midnight, etc.
>
> Surely, there are tons of payroll apps that subtract the punch-out from t=
he 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 di=
fference between two arbitrary Datetimes? Did I overlook something simple? =
Do I need to convert the two to scalar integers first?
See the unix_timestamp() function. Converts date/times to a scalar
integer of the number of seconds since the Unix Epoch.