Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> 于2026年11月7日周六 10:51写道：
>
> BTW, I have a different issue with this query: it seems like "x"
> is just ROW(a), not ROW(a, t2.b, t3.b). It's late and I'm frazzled,
> but isn't that wrong?
I think ROW(a) is intended here: in “JOIN ... USING (a) AS x”, x
aliases only the USING columns, rather than the whole join result.
To make x refer to ROW(a, t2.b, t3.b), the alias would go outside the
parentheses:
“(t t2 JOIN t t3 USING (a)) AS x”
--
Thanks,
Tender Wang