How access table by tableoid

Hi,

can I use a given tableoid (instead of the tablename) to select
columns from that table somehow?

SELECT * FROM ??tableoid??

My first approach was to lauch a subquery of the information_schema
like this:

SELECT * FROM (SELECT relname FROM pg_class WHERE oid=999) AS
tablename

However, it turned out that the subquery returns the refered *column*
which is the 'relname' column but not the table's name. (With other
words: The final result is a single 'relname' column instead of all
columns from the tablename inside the relname column.) This is not was I
intended.

So, I worked around that by peforming two queries: The first to retrieve
the table's name from pg_class via its OID, the second to select the
wanted columns from that table using the table's name as usual.

Can I do it in one go using the table´s OID?

Thank You
Felix