operators +/- with oids

ivan <iv@psycho.pl> writes:

why there are no operators +-*/ to oid data type ?

Why should there be? Addition on OIDs seems like a meaningless
operation, at least for the intended usage of OIDs (namely as
opaque identifiers).

Yes, I know we have < and >= and similar operators on OID, but those
are only there to support btree indexes on OIDs. Equality is the only
user-meaningful operator in the lot, IMHO.

If you are desperate you can cast OID to int4 and then arithmetize it
all you want.

regards, tom lane