title: How can you tell which columns are unused in ALL_TAB_COLS?
body: <p>When you query the ALL_TAB_COLS view on Oracle 9i, it lists columns marked as UNUSED as well as the 'active' table columns. There doesn't seem to be a field that explicitly says whether a column is UNUSED, or any view I can join to that lists the unused columns in a table. How can I easily find out which are the unused columns, so I can filter them out of ALL_TAB_COLS?</p>