Which statement about the CLUSTER BY clause is true?

• A. It defines a clustering key on one or more columns.
• B. It creates multiple independent keys.
• C. It deletes any existing clustering keys.
• D. It automatically updates with every insert.

Answer: (A)

CLUSTER BY designates a clustering key made up of the listed columns. This tells Snowflake how to organize data within micro-partitions so that the query optimizer can prune partitions more effectively when you filter on those columns.

It’s a single composite clustering key, not multiple independent keys. That’s why stating that multiple independent keys are created isn’t correct—the list defines one clustering strategy, not separate keys.

It doesn’t delete existing clustering keys. Defining a clustering key doesn’t remove others on its own.

It doesn’t automatically update with every insert by default. Inserting data doesn’t automatically recluster unless automatic clustering is explicitly enabled as a separate feature.