Robert Haas <robertmh...@gmail.com> writes: > On Wed, Feb 8, 2017 at 4:24 AM, Pantelis Theodosiou <yperc...@gmail.com> > wrote: >> I'm not advocating it but I don't see how introducing new SQL keywords >> breaks backwards compatibility.
> It does at least a little bit. Yes. I think a new set-operation keyword would inevitably have to be fully reserved --- UNION, INTERSECT, and EXCEPT all are --- which means that you'd break every application that has used that word as a table, column, or function name. Generally speaking, we try very darn hard not to introduce new reserved words that are not called out as reserved in the SQL standard. (And even for those, we've sometimes made the grammar jump through hoops so as not to reserve a word that we didn't reserve previously.) regards, tom lane -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers