Just a guess, but it seems to me that since the join is using col1 and col2 there is no ambiguity. They should be the same no matter which table it comes from.
Edward W. Rouse -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Emi Lu Sent: Friday, August 22, 2008 4:12 PM To: pgsql-sql@postgresql.org Subject: [SQL] Why *no* ambig.uous complain in select part? Good morning, Just notice one small thing, and need your information about select select col1, col2 from table1 left join table2 using (col1, col2) ; This query never complain about ambiguous columns of col1 and col2 in the select part. My guess is: (1) col1, col2 always return table1.col1, table1.col2 (2) because using (col1, col2) that's why, table name is not necessary in select part Am I wrong? Please advise? Thank you! -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
