On Tue, Sep 13, 2016 at 11:38 PM, Ashutosh Bapat <ashutosh.ba...@enterprisedb.com> wrote: > On Tue, Sep 13, 2016 at 10:28 PM, Robert Haas <robertmh...@gmail.com> wrote: >> On Tue, Sep 6, 2016 at 9:07 AM, Ashutosh Bapat >> <ashutosh.ba...@enterprisedb.com> wrote: >>> That's not true with the alias information. As long as we detect which >>> relations need subqueries, their RTIs are enough to create unique aliases >>> e.g. if a relation involves RTIs 1, 2, 3 corresponding subquery can have >>> alias r123 without conflicting with any other alias. >> >> What if RTI 123 is also used in the query? > > Good catch. I actually meant some combination of 1, 2 and 3, which is > unique for a join between r1, r2 and r3. How about r1_2_3 or > r1_r2_r3?
Sure, something like that can work, but if you have a big enough join the identifier might get too long. I'm not sure why it wouldn't work to just use the lowest RTI involved in the join, though; the others won't appear anywhere else at that query level. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers