Which transformation is NOT supported when loading with COPY?

• A. Column Reordering
• B. Column Renaming
• C. Casts
• D. Truncating text strings

Answer: (B)

When loading data with COPY, you map source fields into the target table columns, and Snowflake lets you control that mapping in a few flexible ways. You can reorder which source fields land in which target columns by listing the target column names in the desired order, you can rely on Snowflake’s casting to convert data types as needed, and you can enable truncation of strings that exceed a column’s defined width using file format options. What you can’t do is rename a column on the fly during the load—the column names in the target table must be kept, and any renaming would require a separate step after loading (such as a view or a follow-up transformation). So the operation that isn’t supported during COPY load is renaming columns.