On Thu, Jul 28, 2011 at 5:09 PM, Tom Lane
<tgl@sss.pgh.pa.us> wrote:
> It seems like we're being inconsistent here in allowing 'where xid =
> integer' but not allowing 'where xid != integer'.
Well, if you look into pg_operator you'll soon find that there are
exactly two built-in operators that accept type xid: "=(xid,xid)" and
"=(xid,integer)" (where I'd say the latter is just a kluge).
There hasn't previously been any demand to flesh it out more than that.
Do you have an actual use-case where <> would be helpful, or is this
just experimentation?
I'm not sure yet. I was doing some thinking about ways to do incremental backups
(at least for inserted/updated rows, deleted rows present a different challenge),
and was just doing some simple queries to see what worked and what didn't..
It also appears you cannot group on a column of type xid.
Would adding a <> operator enable that?
--
Mike Nolan