"Alessandro Depase" <alessandro(dot)depase(at)libero(dot)it> writes:
> I got the error message reported in the subject and I could not find anythi=
> ng about it anywhere.
It's a bug, but we can't do much about it unless you provide a
reproducible example. In addition to the query itself, schemas
for the tables involved would be needed (use pg_dump -s). Test
that you can load the schema dump into an empty database, execute
the problem query, and get the failure.
regards, tom lane