From what i know, Aliases are literals, they are not variables, hence they cannot be derived from something. you can derive them outside the scope of normal SQL by using functions or shell scripts, but probably not inside an SQL context.
> _But_, I don't want to give the alias explicitely, instead it should be > taken from a second table 'colnames', i.e. something like the line I sent in > my initial mail. Any idea?
Then you'll have to build a query in plpgsql and execute it to get what you want. You can't do what you're trying to do in normal SQL. At least I don't think it's possible.
