How about using a system column eg, ctid, for the CASE WHEN conversion; in Rushabh's example the reference to "r1" would be converted with "CASE WHEN r1.ctid IS NOT NULL THEN ROW(r1.empno, r1.ename, r1.job, r1.mgr, r1.hiredate, r1.sal, r1.comm, r1.deptno) END". IMO I think that that would be much simpler than Ashutosh's approach.
A foreign table can have a view, a regular table, another foreign table or a materialised view a its target. A view does not support any of the system columns, so none of them are available.
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Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company
