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
