Re: Aggregate functions with FROM clause and ROW_COUNT diagnostics

Alexey Dokuchaev <danfe@nsu.ru> writes:
> Quick reality check
> question: are count(*) vs. count(_) equivalent above?

Only if _ is guaranteed non-null ... which, as a rowtype result, it
probably is.  But I'd use count(*) if you're concerned about speed.

            regards, tom lane