I'm sure you can but I'm not smart enough to figure that out (I think some quoting is missing):
EXECUTE 'SET ROLE ' || (SELECT rolname FROM pg_roles WHERE oid = 17026)
But I wouldn't use those oid's because you are leaking some implementation detail, it's probably best to just stick with the actual role names instead of a reference.
EXECUTE 'SET ROLE ' || (SELECT rolname FROM pg_roles WHERE oid = 17026)
But I wouldn't use those oid's because you are leaking some implementation detail, it's probably best to just stick with the actual role names instead of a reference.