[HACKERS] Fixing DISTINCT ON for duplicate keys

2008-07-31 Thread Tom Lane
I looked into this trouble report: http://archives.postgresql.org/pgsql-sql/2008-07/msg00123.php The problem is that by the time we get to transformDistinctClause(), any duplicate entries in the ORDER BY list have been eliminated (see addTargetToSortList). But transformDistinctClause expects a

Re: [HACKERS] Fixing DISTINCT ON for duplicate keys

2008-07-31 Thread David Fetter
On Thu, Jul 31, 2008 at 01:38:37PM -0400, Tom Lane wrote: I looked into this trouble report: http://archives.postgresql.org/pgsql-sql/2008-07/msg00123.php Comments? It seems to me that DISTINCT ON is just a special case of the more general windowing functions

Re: [HACKERS] Fixing DISTINCT ON for duplicate keys

2008-07-31 Thread Tom Lane
David Fetter [EMAIL PROTECTED] writes: It seems to me that DISTINCT ON is just a special case of the more general windowing functions http://archives.postgresql.org/pgsql-hackers/2008-07/msg01277.php Harada-san has been working on. Could these use the same machinery? Perhaps at some point we

Re: [HACKERS] Fixing DISTINCT ON for duplicate keys

2008-07-31 Thread David Fetter
On Thu, Jul 31, 2008 at 03:10:35PM -0400, Tom Lane wrote: David Fetter [EMAIL PROTECTED] writes: It seems to me that DISTINCT ON is just a special case of the more general windowing functions http://archives.postgresql.org/pgsql-hackers/2008-07/msg01277.php Harada-san has been working on.