I found PostgreSQL accepts UNION DISTINCT but documents don't mention it. http://www.postgresql.org/docs/9.0/static/sql-select.html#SQL-UNION
select_statement UNION [ ALL ] select_statement 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? 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
