n Fri, Sep 30, 2011 at 11:08 PM, Jan Steinman <Jan@stripped> 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 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?
See the unix_timestamp() function. Converts date/times to a scalar
integer of the number of seconds since the Unix Epoch.