"Karl O. Pinc" <kop@xxxxxxxx> writes: > I'm doing some complicated joining and am getting error > messages about unknown relations and can't figure out > what's up. I'm wondering if "as" aliasing gives > an alias to the product of a join, not just the > one table that appears immediately in front of the > "as". ? If you write ... FROM (a JOIN b) AS c then (1) the alias c refers to the whole join result, not either a or b and (2) you can't directly reference the table aliases a or b from outside this JOIN clause: the alias c masks them. This behavior is per SQL spec. > The other question that sprang to mind while working > on this was whether there's performance (or any other) > implications of using WHERE conditions instead of > JOIN inside FROM. See http://www.postgresql.org/docs/8.0/static/explicit-joins.html (adjust URL to match the major version you are running, as the answers vary). regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
