Tom Lane wrote
> > How about replacing "expression [ , ... ]" by "parameter_list" in the description,
> > and then stating that parameter_list can be either a single expression or ,
> > if the particular aggregate function accepts it (for which, consult that function's reference),
> > a comma-separated list of expressions.
>
> That's just as wrong. As we tried to explain before, the
> parenthesized-list syntax is a row constructor, so it only works
> in cases where the aggregate function can accept a composite
> argument type. Most don't.
>
But surely not *all* cases of a multi-expression parameter list of an aggregate function are row constructors are
they? What about
select parent_id, name, GROUPING(parent_id , name), count(*) FROM mytable GROUP BY ROLLUP(parent_id , name);
In the piece "GROUPING(parent_id , name)" ,
is "(parent_id , name)" a row constructor or a list of two expressions?
Or are you saying those are one and the same thing?
Cheers, John