2010/10/15 Tom Lane <t...@sss.pgh.pa.us>: > Hitoshi Harada <umi.tan...@gmail.com> writes: >> UNION DISTINCT is nothing more than UNION itself, but gram.y >> definitely accept it and the SQL standard describes it as well. Should >> we add DISTINCT to docs? > > I think it'd be hard to describe without confusing people, because > while DISTINCT is a noise word there, it's definitely not a noise > word after SELECT. And the way that the reference pages are laid > out, it's hard to connect different descriptions of the same > keyword to different usages. If you can think of a non-forced > way of describing this, fine. But I don't have a problem with > leaving it as an undocumented standards-compliance nit.
I thought adding DISTINCT next to ALL is enough like select_statement UNION [ ALL | DISTINCT ] select_statement and say "UNION DISTINCT is identical to UNION only" or something. That sounds not so confusing with DISTINCT clause description. Regards, -- Hitoshi Harada -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
