David Gagnon <dgagnon(at)siunik(dot)com> writes:
> update test set id=test2.id from test2 where id=test2.id;
>
> ERROR: column reference "id" is ambiguous
It's complaining about the second use of "id", which could mean either
"test2.id" (which would be a self-join) or "test.id" (which is what
you want).
-Doug