Rule rewrite to possible union?

Here's what I'd like to happen, but I'm not seeing how it can be done.

Say we have this simple table:

CREATE TABLE foo (
id integer,
foo varchar
);

and then many tables along these lines:

CREATE TABLE ud1_foo (LIKE foo);
CREATE TABLE ud2_foo (LIKE foo);

What I'd like is to do is select against foo and if there is an id in
the where clause equal to 1 or 2 add a union with the appropriate
table. I could easily do this at the application level, but this is
for a migration (the ud tables are going away) and I'd like to
minimize the number of transient application code changes wherever
possible. Is there any way I can make this happen?

Erik Jones

Software Developer | Emma®
erik(at)myemma(dot)com
800.595.4401 or 615.292.5888
615.292.0777 (fax)

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