Which query correctly retrieves the clustering depth for the table TPCH_ORDERS when only the table name is provided?

• A. select system$clustering_depth('TPCH_ORDERS');
• B. select system$clustering_depth('TPCH_ORDERS', '(C2, C9)');
• C. select system$clustering_depth('TPCH_ORDERS', '(C2, C9)', 'C2 = 25');
• D. select system$clustering_ratio('TPCH_ORDERS');

Answer: (A)

When you want the overall clustering depth for a table, use the system$clustering_depth function with only the table name. This form computes the depth across the table’s clustering keys without narrowing to specific keys, giving you the general depth value for that table. Providing extra arguments would limit the depth calculation to particular clustering keys or apply additional filters, which isn’t what you want when you need the table-wide depth. The query that passes just the table name matches this scenario, making it the correct choice. The other options either specify specific clustering keys or use a different metric (clustering ratio), which don’t return the table-wide clustering depth.