SQL derived/virtual colimn

All,

I seem to remember hearing something about the ability of SQL to define what
I would call virtual columns in a table. (Or was it views only?)

A very simple example would be if a table had fields "Sales" and "Cost",
then in a Create Table you could specify a field called "Profit" and define
it as "Sales - Cost". Am I dreaming? I could be because my googling hasn't
turned up examples, nor do I seem to see it in the IBM manuals. OTOH, SQL
could refer to it by some term other than "virtual" or "derived". That has
happened to me more times than not.

Thanks.