Re: Variadic aggregates vs. project policy

David Johnston <polobo(at)yahoo(dot)com> writes:
>>> If we alter syntax for mitigation purposes I'd want to consider requiring
>>> parentheses around the columns that belong to the ORDER BY instead of
>>> using the full extended syntax of WITHIN GROUP.

Unfortunately, that ORDER BY syntax is specified by the SQL standard,
and they didn't say anything about parentheses. We don't get to
require parens there.

The particular case that's standardized is only array_agg():

<array aggregate function> ::=
ARRAY_AGG
<left paren> <value expression> [ ORDER BY <sort specification list> ]
<right paren>

but, as we customarily do, we didn't restrict the feature to be used only
with that aggregate.

regards, tom lane