Connect with your schema and run the sql scripts
SET LINESIZE 32000;
SET PAGESIZE 40000;
SET LONG 50000;
SELECT t.table_name,
t.column_name
FROM user_tab_columns t
WHERE t.nullable = 'Y'
AND t.num_distinct = 0 AND t.table_name='TABLE_NAME';
For example:
SET LINESIZE...
