On Tue, 11 Jan 2005, Terry Lee Tucker wrote: > As you can see, this truck is going to be 2 hours late. The return value I'm > looking for is the difference between Appt. Interval and Travel Interval, as > in: return (appt_interval - travel_interval). This value will be stored in a > column of type interval. I would like for late values to be shown as > negative. @ -2 hours. I thought that subtracting the larger interval from > the small would return this but it is always the absolute value. The > documentation states: > > interval values can be written with the following syntax: > > [@] quantity unit [quantity unit...] [direction] > > Where: quantity is a number (possibly signed); > > Considering the above statement I believed that I could show this difference > as a negative value but I haven't been able to figure out how to do it. Can I > do this, and if so, how? Well, when I try this with constant values on my 7.4 or 8.0 dev system I get: select '3 days 4 hours 17 mins'::interval - '3 days 6 hours 17 mins'::interval; ?column? ----------- -02:00:00 (1 row) Can you give a full example? ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to majordomo@xxxxxxxxxxxxxx)