DAA-C01 Exam Dumps : SnowPro Advanced: Data Analyst Exam

Manually defining table structures for complex semi-structured files like Parquet can be error-prone and time-consuming. Snowflake provides a specific automation workflow to handle this, involving the detection of the file's internal schema and the dynamic creation of a matching table.

The process starts with the INFER_SCHEMA function. Because Parquet files are self-describing, they contain metadata about their columns and data types. INFER_SCHEMA reads this metadata from files in a stage and returns a list of column names and types. To turn this list into an actual table, the analyst uses the CREATE TABLE ... USING TEMPLATE syntax. This command takes the output of INFER_SCHEMA as an input and automatically builds a table with the corresponding definition.

Evaluating the Options:

Option A is incorrect because CREATE TABLE LIKE is used to copy the structure of an existing table, not to build a new one from file metadata.

Option C and D are incorrect because GENERATE_COLUMN_DESCRIPTION is a helper function used to create a formatted string of column definitions, but it is not the primary command used with USING TEMPLATE for automated table creation.

Option B is the Correct answer. The combination of INFER_SCHEMA (to find the columns) and USING TEMPLATE (to build the table) is the standard Snowflake pattern for schema-on-read automation in Data Ingestion workflows.

Working with semi-structured data types like Arrays is a core competency for a Snowflake Data Analyst. In Snowflake, arrays are zero-indexed, meaning the first element is at position 0. Consequently, the index of the last element is always the total number of elements minus one ($Size - 1$).

To retrieve an element from a specific index, Snowflake provides the GET() function. This function takes the array column and the calculated index as arguments. When combined with ARRAY_SIZE(), which returns the total count of elements in the array, the formula ARRAY_SIZE(COL_B)-1 accurately targets the final index regardless of the array's length.

Evaluating the Options:

Option B is incorrect because using ARRAY_SIZE as the index directly (without subtracting 1) results in an "out-of-bounds" error or returns NULL, because the index equals the length (e.g., in an array of 3 items, the max index is 2).

Option C is incorrect. While some programming languages (like Python) allow negative indexing to start from the end, Snowflake SQL does not support this shorthand for arrays; it would simply return NULL.

Option D is incorrect because LAST_VALUE is an Analytic/Window function used to find the last row in a sorted result set, not the last element within a single array cell.

Option A is the 100% correct approach. It uses the standard, robust method for dynamic index calculation. This ensures that even if different rows have arrays of different lengths, the query will always successfully "pluck" the final item from each. This skill is vital for Data Transformation tasks, such as extracting the most recent status from a history array.

This scenario requires a specific combination of Snowflake's extensibility features: the ability to run Python (pandas) code, the ability to return multiple rows for a single input (tabular output), and high performance through vectorization.

A User-Defined Table Function (UDTF) is the correct architectural choice when an input value needs to be expanded into a set of rows. While a standard UDF returns exactly one value per input row, a UDTF can return zero, one, or many rows, making it ideal for "parsing" or "splitting" tasks. By using a Vectorized UDTF (specifically utilizing the Python handler with pandas), the Analyst can process blocks of rows as pandas DataFrames or Series. This is significantly more efficient than processing one row at a time because it reduces the overhead of the Snowflake-to-Python execution engine.

Evaluating the Options:

Option A is incorrect because a standard UDF can only return a single scalar value per input row, making it impossible to "return multiple rows of parsed output."

Option C is incorrect because External Functions are used to call code hosted outside of Snowflake (like an AWS Lambda). While they can process data, they introduce network latency and are not the native way to run pandas code for internal joins.

Option D is incorrect because Stored Procedures are generally used for administrative tasks and procedural logic. While they can return tables, they cannot be directly "joined" with other tables in a standard SELECT statement in the same way a UDTF can.

Option B is the correct choice. It satisfies the requirement for pandas integration, provides the necessary multi-row output via the process and end_partition methods, and allows the analyst to use the LATERAL keyword to join the parsed results directly with existing tables in a single SQL statement.