I wrote:
> One possibility is to forget all the parens and say that the display
> looks like
> type1, type2 WITHIN GROUP type3, type4
> Please don't object that that doesn't look exactly like the syntax
> for calling the function, because it doesn't anyway --- remember you
> also need ORDER BY in the call.
Actually, now that I think of it, why not use this syntax for declaration
and display purposes:type1, type2 ORDER BY type3, type4
This has nearly as much relationship to the actual calling syntax as the
WITHIN GROUP proposal does, and it's hugely saner from a semantic
standpoint, because after all the ordering columns are ordering columns,
not grouping columns.
regards, tom lane