Snowflake DAA-C01 - SnowPro Advanced: Data Analyst Exam

To correctly predict the output of this query, a Data Analyst must understand how Snowflake handles semi-structured data (JSON), specifically regarding path notation, data type casting, and the display of VARIANT values in the Snowsight UI.

1. Variant vs. Casted Types (Display): When you access a value within a JSON object using colon notation (e.g., json_col:employee.phone[0]), the resulting value is of the VARIANT data type. In the Snowflake Snowsight results pane, VARIANT strings are displayed with double quotes (e.g., "+1 223-256-7330"). However, when you explicitly cast a variant to a string type using the double-colon syntax (e.g., ::varchar), Snowflake extracts the value as a native SQL string, which is displayed without quotes (e.g., +1 028-735-4521).

2. Handling Empty Strings vs. Out-of-Bounds: In the provided JSON exhibit, the phone array contains four elements at indices 0, 1, 2, and 3. The elements at indices 2 and 3 are empty strings (""). When these are queried, Snowflake returns the empty string variant, which appears as "" in the result set. The query also attempts to access phone[4]. Since the array only has four elements (max index 3), index 4 is out-of-bounds. In Snowflake, accessing a non-existent index in an array or a non-existent key in an object returns NULL.

Evaluating the Options based on the exhibit:

Option B correctly reflects all these behaviors: WORK_PHONE is in quotes (Variant), OFFICE_PHONE1 is not in quotes (Casted), OFFICE_PHONE2 and OFFICE_PHONE3 show the empty strings present in the JSON, and OFFICE_PHONE4 correctly shows null for the out-of-bounds access.

Option A is incorrect because it misses the quotes for the variant column and shows the out-of-bounds index as an empty string instead of null.

Option C is incorrect because it fails to account for the empty strings present at indices 2 and 3.

Option D incorrectly mixes the casting logic and display.

This question tests the "Schema-on-Read" proficiency required of a SnowPro Advanced: Data Analyst, specifically the ability to predict exactly how transformed semi-structured data will materialize for end-users.

Snowflake Cortex ML functions, such as FORECAST, return a tabular result set when called using the instance method syntax (e.g., CALL modelX!FORECAST(...)). While this output is visible in the Snowsight results pane, the CALL statement itself cannot be used directly as a subquery within a standard INSERT INTO or CREATE TABLE AS SELECT (CTAS) statement.

To persist the results of a model's prediction into a permanent table (tableX), the Data Analyst must utilize the RESULT_SCAN table function. Snowflake stores the results of every query and function call in a temporary cache for 24 hours. The RESULT_SCAN function allows you to treat that cache as a queryable table.

The standard workflow is:

Execute the forecast: CALL modelX!FORECAST(FORECASTING_PERIODS => 12);

Immediately after, use the LAST_QUERY_ID() function to identify the query that generated the forecast results.

Create the table by querying that result set: CREATE TABLE tableX AS SELECT * FROM TABLE(RESULT_SCAN(LAST_QUERY_ID()));

Evaluating the Options:

Option A is incorrect because the CALL syntax does not support a direct INTO clause for table creation.

Option B is incorrect because passing a table as an argument is part of the training or input phase, not the output persistence phase.

Option D is overly complex and contains non-standard terminology ("List the cache content").

Option C is the 100% correct answer. It reflects the required "post-processing" step in the Snowflake Data Cloud to bridge the gap between procedural model calls and relational table storage.

In data modeling and analysis, "rotating" data is a common task used to normalize datasets for reporting or visualization. The operation of taking multiple columns (like the individual months in the source image) and turning them into values within a single column (like the "MONTH" column in the target image) is specifically known as unpivoting.

The UNPIVOT relational operator in Snowflake allows an analyst to transform a "wide" table format into a "narrow" (or "long") table format. In the wide format shown in the first image, data is distributed across columns named JAN, FEB, MAR, and APRIL. While this is often easier for humans to read in a spreadsheet, it is difficult to query for trends. By applying UNPIVOT, Snowflake collapses these columns into two new ones: one for the name of the original column (the attribute, such as "MONTH") and one for the value that was stored in that column (the metric, such as "SALES").

Evaluating the Options:

Option A (PIVOT) is the opposite of the required action. It is used to turn unique values from one column into multiple separate columns (narrow to wide), which is not what is happening in the exhibit.

Option C (INTERSECT) is a set operator that returns only the distinct rows that are present in both the first and second query results. It does not perform data rotation.

Option D (EXCEPT) is a set operator that returns rows from the first query that are not present in the second.

Option B is the 100% correct answer. It is the dedicated relational operator for converting column headers into row values, which is exactly the transformation required to move from the first image to the second. Mastering this operator is a critical skill for any SnowPro Advanced: Data Analyst when preparing messy source data for high-performance analytics.

Managing complex pipelines involving multiple dependent tasks requires an understanding of Task Graphs (DAGs). In Snowflake, a DAG is a series of tasks with parent-child relationships. If a parent task (like STEP10) fails, Snowflake automatically cancels the execution of all child tasks (like STEP11 and STEP12) to prevent data corruption or inconsistent states.

To recover from such a failure, Snowflake provides the RETRY LAST clause within the EXECUTE TASK command. The critical nuance here is that you do not target the individual failed task; instead, you target the root task of the graph (in this case, ETLDAILY). When you run EXECUTE TASK RETRY LAST;, Snowflake identifies the most recent failed run of that graph and intelligently resumes execution starting from the failed task (STEP10) and continues through all subsequent dependent tasks that were previously skipped.

Evaluating the Options:

Option A is incorrect because attempting to execute just STEP10 would treat it as a standalone run and would not automatically trigger the dependent logic of the ETLDAILY graph structure.

Options C and D are incorrect because RESUME is a DDL command used to change a task's state from SUSPENDED to STARTED (enabled). It does not trigger an immediate execution or a retry of a failed run; it merely allows the task to run on its next scheduled interval.

Option B is the 100% correct answer. It utilizes the dedicated Snowflake mechanism for graph recovery, ensuring that the entire pipeline is completed starting from the point of failure without re-running successfully completed earlier steps.

One of the most powerful features of the Snowsight interface for a Data Analyst is the automatic data profiling provided in the results pane. Snowflake automatically calculates statistics and visual distributions for the result set of any query executed in a worksheet, provided the result set is not excessively large.

When the Analyst views the query results, they can simply click on the column header for the "total amount" column. This action opens a summary pane that displays key descriptive statistics such as the mean, sum, and a histogram showing the frequency distribution of the values in that specific column. This allows for immediate visual analysis of data skew, outliers, or common ranges without requiring the analyst to write additional SQL or move the data to an external visualization tool.

Evaluating the Options:

Option A is the Correct answer. This is the fastest, built-in way to perform "exploratory data analysis" (EDA) on a result set within the UI.

Option B and C are incorrect because while Snowsight does have a "Chart" tab, creating a chart requires manual configuration and is a separate step from the automatic profiling features found in the column headers.

Option D is incorrect because calling the WIDTH_BUCKET function would require the Analyst to run the query again with modified SQL logic, which explicitly contradicts the requirements of the question.

This feature significantly enhances the Data Analysis workflow by providing "at-a-glance" insights into data quality and distribution directly within the development environment.

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.

In Snowsight, worksheets and dashboards are tightly integrated to facilitate a smooth transition from data exploration to formal reporting. When a Data Analyst has already done the "heavy lifting"—cleaning and preparing data within standalone worksheets—Snowflake provides a direct way to convert those worksheets into dashboard tiles.

The "least operational overhead" method is to Move the existing worksheets into the dashboard. When you are in the dashboard view, you can select the option to add a tile and then choose an existing worksheet from your folders. This "Move" or "Add from Worksheet" action preserves the entire SQL statement, any formatting applied to the results, and the visualization settings (charts) that were already configured in the worksheet.

Evaluating the Options:

Option B and C are technically possible but require significantly more effort (manual copy-pasting, switching windows, re-naming tiles). This increases the risk of human error and is not considered a high-efficiency workflow in Snowsight.

Option D is the most complex and overhead-intensive option, requiring the analyst to sift through system logs to recover code they already have access to in their UI.

Option A is the 100% correct answer. By moving or importing the worksheet directly into the dashboard as a tile, the analyst maintains the link between the development work and the final presentation with just a few clicks. Note that once a worksheet is moved into a dashboard, it essentially becomes a "tile" and is managed as part of the dashboard object.

In Snowflake, a Stored Procedure is the primary object used for procedural logic and the encapsulation of multiple SQL statements. Unlike standard functions that are typically restricted to returning a single value or a table based on an input, Stored Procedures are designed to perform administrative tasks, wrap complex business logic, and execute a sequence of operations—such as DDL (Data Definition Language) and DML (Data Manipulation Language) commands—within a single callable object.

Modular code development is facilitated by Stored Procedures because they allow analysts and developers to write logic once and reuse it across various workflows. For example, a procedure can be written to truncate a staging table, call a COPY INTO command, and then execute several INSERT statements into a final fact table. This "wrapper" approach ensures consistency, as any change to the logic only needs to be updated in the procedure definition rather than in every script or task that uses it.

Evaluating the Options:

Option B is incorrect because a Materialized View is a pre-computed result set used to improve query performance; it does not "encapsulate a series of statements" for procedural execution.

Option C is incorrect because while User-Defined Functions (UDFs) provide reusability, they are generally intended for calculations or data transformations that return a result. They are much more restricted than procedures; for instance, a UDF cannot execute DDL commands like CREATE TABLE.

Option D is incorrect because a Common Table Expression (CTE) is a temporary named result set defined within the execution scope of a single SELECT, INSERT, UPDATE, or DELETE statement. It is not a persistent database object and cannot be reused across different sessions or scripts.

Option A is the correct answer. Snowflake Stored Procedures can be written in multiple languages (JavaScript, Snowflake Scripting/SQL, Python, Java, or Scala), providing the flexibility needed for sophisticated, modular automation in a data pipeline.

The SAMPLE clause (or TABLESAMPLE) is used in Snowflake to return a subset of rows from a table. When performing analysis on massive datasets, sampling allows for faster query execution and reduced credit consumption while still providing a statistically representative view of the data.

There are two primary methods of sampling in Snowflake: BERNOULLI (row-based) and BLOCK (partition-based). The query in this question uses BLOCK sampling, which selects a specific percentage of micro-partitions (blocks) rather than individual rows. This method is significantly faster for very large tables because it avoids the overhead of scanning every single row within a block; it either includes the entire block or skips it entirely.

Evaluating the Syntax:

Probability: The value inside the parentheses (0.012) represents the probability percentage for inclusion. Unlike some systems that might use decimals (where 1.0 = 100%), Snowflake treats this number as a direct percentage. Therefore, 0.012 is exactly 0.012%, not 1.2%.

Repeatable/Seed: The REPEATABLE clause (or SEED) followed by a number (99992) ensures that the sampling is deterministic. If the underlying data does not change, running this same query multiple times with the same seed will return the exact same "random" subset of blocks.

Evaluating the Options:

Options A and C are incorrect because they misinterpret the probability 0.012 as 1.2%.

Option D is incorrect because it mistakenly identifies the seed number 99992 as a target row count.

Option B is the 100% correct answer as it accurately identifies the sampling method (BLOCK), the correct percentage probability (0.012%), and the role of the seed (99992).