Re: Difference between two times as a numeric value in a stored procedure.

On Fri, Jun 04, 2004 at 10:11:57 +0200,
Stijn Vanroye <s(dot)vanroye(at)Farcourier(dot)com> wrote:
> The working of the functions is not the problem, but the return type is. I can't seem to find a way to substract two time values (or timestamp values) and get a numeric/float value. I always get the INTERVAL datatype. For example, in stead of 4:30 i would like 4.5 as a result. I have searched the documentation but could not find any way to substract time/timestamp values and get a numeric/float as a result. When I try to CAST the interval to a numeric or float value I get an error (cannot cast time without tz to ...). Same goes for trying to cast the beginvalues and then substract them. Does anyone have any idea how I can solve/circumvent this problem? Is there a function I can use?

You can use EXTRACT to extract the EPOCH from the interval which will
be the number of seconds in the interval. You can then use arithmetic
(/60.) on that number to get fractional hours.