On Sun, Sep 18, 2011 at 5:39 AM, Kerem Kat <kerem...@gmail.com> wrote: > I am new to postgresql code, I would like to start implementing easyish TODO > items. I have read most of the development guidelines, faqs, articles by > Greg Smith (Hacking Postgres with UDFs, Adding WHEN to triggers). > The item I would like to implement is adding CORRESPONDING [BY > (col1[,col2,...]])] to INTERSECT and EXCEPT operators. > Can anyone comment on how much effort this item needs?
This seems reasonably tricky for a first project, but maybe not out of reach if you are a skilled C hacker. It's certainly more complicated than my first patch: http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=a0b76dc662efde6e02921c2d16e06418483b7534 I guess the first question that needs to be answered here is ... what exactly is this syntax supposed to do? A little looking around suggests that EXCEPT CORRESPONDING is supposed to make the correspondence run by column names rather than by column positions, and if you further add BY col1, ... then it restricts the comparison to those columns. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers