PL-300 Practice Exam 58 — 20 Questions

Question 1

You are troubleshooting a Power Query transformation that groups sales data by ProductID. The query runs slowly and you suspect the filter is being applied after loading all rows. What change would improve performance by pushing the filter to the source?

Accepted Answer

Replace the first three lines with a native SQL query that includes the WHERE clause. Option D is correct because pushing filter logic to the source database via a native SQL query with a WHERE clause reduces the amount of data loaded into Power Query. This leverages query folding, which allows the source (e.g., SQL Server) to perform the filtering before data is transferred, significantly improving performance for large datasets.

Answer

Disable the 'Enable load' option for the SalesTable

Answer

Use CALCULATE in DAX to filter

Answer

Add a 'Table.Buffer' step after the filter

Question 2

You need to create a date table in Power BI using DAX. Which function should you use to generate a continuous list of dates?

Accepted Answer

CALENDAR.. The CALENDAR function in DAX generates a single-column table of dates that starts from a specified start date and ends at a specified end date, creating a continuous list of all dates in that range. This is the correct function to use when you need to create a date table for time intelligence calculations in Power BI.

Answer

CALCULATE.

Answer

TODAY.

Answer

DATEVALUE.

Question 3

Which TWO options are valid methods to combine multiple tables in Power Query?

Accepted Answer

Merge. Option C (Merge) is correct because Merge in Power Query performs a join-like operation that combines columns from two tables based on a matching key, similar to SQL JOINs. Option E (Append) is correct because Append stacks rows from multiple tables with the same columns, akin to SQL UNION ALL. Both are native Power Query operations for combining tables.

Answer

Join

Answer

Concatenate

Answer

Union

Question 4

You need to prepare data from a folder containing multiple CSV files with identical structure. What is the most efficient way to load all files into a single table?

Accepted Answer

Use the 'From Folder' data source and then click 'Combine & Transform Data'. Option B is correct because the 'From Folder' data source in Power Query automatically detects multiple CSV files with identical structure and provides a 'Combine & Transform Data' button that merges them into a single table in one step. This is the most efficient method as it eliminates the need for manual imports or scripting, leveraging Power Query's built-in file combination logic.

Answer

Import each CSV file separately and then append them

Answer

Write a Python script in Power Query to read and combine files

Answer

Use a dataflow to connect to the folder and apply the 'Combine Files' transformation

Question 5

You are importing data from a SQL Server view into Power BI. The view contains calculated columns that are expensive to compute. You want to minimize the load on the source database during refresh. What should you do?

Accepted Answer

Import the raw data and perform transformations in Power Query.. Option A is correct because importing raw data and performing transformations in Power Query offloads the computational burden from the SQL Server source to Power BI's mashup engine. This minimizes load on the source database during refresh, as expensive calculated columns are not executed on SQL Server. Power Query can apply transformations after the data is extracted, reducing the need for server-side processing.

Answer

Enable query folding to push transformations to SQL Server.

Answer

Use a native SQL query in Power Query to perform calculations.

Answer

Create a materialized view in SQL Server with the calculations.

Question 6

Refer to the exhibit. You are reviewing a Power BI data source credential configuration. The Azure Blob Storage data source uses 'Anonymous' credentials. However, the refresh fails with an error indicating that the blob container is private and requires authentication. Which change should you make?

Accepted Answer

Change credential type to 'Account Key' and provide the storage account key.. Azure Blob Storage containers that are private require authentication. The 'Account Key' credential type in Power BI uses the storage account key to authenticate via the Azure Storage REST API, which is the correct method for accessing private blob containers. Anonymous access only works when the container is configured for public access.

Answer

Change credential type to 'Service Principal' and provide the app ID and secret.

Answer

Change credential type to 'Basic' and provide the storage account name and key.

Answer

Change credential type to 'Windows' for the Azure Blob datasource.

Question 7

You are importing data from an Excel workbook that contains multiple sheets. Each sheet has similar structure but different data for different regions. You need to combine all sheets into a single table for analysis. What should you do?

Accepted Answer

In Power Query Editor, use Append Queries to combine the sheets.. Option B is correct because the Append Queries operation in Power Query Editor is designed to combine rows from multiple tables or queries with similar column structures into a single table. Since each sheet in the Excel workbook contains data for different regions with the same structure, appending them stacks the rows, creating a unified dataset for analysis.

Answer

In Power Query Editor, use Merge Queries to combine the sheets.

Answer

Copy and paste the data from each sheet into a master sheet in Excel.

Answer

In Power Query Editor, use Group By to consolidate the data.

Question 8

You are designing a Power BI data model for sales analysis. The source data includes a table with columns: OrderID, CustomerID, ProductID, OrderDate, Quantity, and UnitPrice. You need to support time intelligence calculations (e.g., year-to-date sales) and avoid creating a separate date table. What should you do?

Accepted Answer

Use the CALENDAR function in a calculated table to create a date table and mark it as a date table.. Option A is correct because time intelligence functions in Power BI (e.g., TOTALYTD, SAMEPERIODLASTYEAR) require a contiguous, continuous date table marked as a date table. Using the CALENDAR function creates a calculated date table that meets this requirement, enabling accurate year-to-date and other time-based calculations without relying on the auto date/time feature or direct column usage.

Answer

Enable the auto date/time option in Power BI Desktop settings.

Answer

Use the OrderDate column directly in time intelligence measures.

Answer

Create a calculated column for fiscal year using the OrderDate column.

Question 9

You are importing data from a REST API that returns JSON. The JSON structure includes nested arrays. You need to transform the data into a flat table structure in Power Query. Which transform should you apply?

Accepted Answer

Use 'Expand to New Rows' on the list columns. Option A is correct because the 'Expand to New Rows' transform (found under the 'Transform' tab in Power Query) is specifically designed to flatten nested list columns—such as arrays within JSON—by creating a new row for each element in the list. This converts the hierarchical JSON structure into a flat table, which is the required outcome for further analysis in Power BI.

Answer

Use 'Merge Queries' to combine the nested data

Answer

Use 'Pivot Column' on the nested columns

Answer

Use 'Unpivot Columns' on the record columns

Question 10

Refer to the exhibit. You are reviewing a DAX measure in Power BI. The measure is intended to calculate total sales for the year 2024. However, when used in a visual with a slicer on 'Sales[Date]', the measure does not respect the slicer selection. What is the most likely reason?

Accepted Answer

The FILTER function overrides the slicer filter context.. Option A is correct because the FILTER function in the measure creates a new filter context that overrides the existing slicer filter context on 'Sales[Date]'. When CALCULATE evaluates the expression, it applies the FILTER as a table modifier, which replaces any external filters on the Date column, causing the slicer to be ignored. This is a common DAX behavior where explicit filter arguments in CALCULATE take precedence over existing filter contexts.

Answer

The CALCULATE function removes all filters by default.

Answer

The measure should use ALL(Sales[Date]) to respect slicers.

Answer

The DATE function syntax is incorrect.

Question 11

Which TWO data source types can be used with Power BI dataflows?

Accepted Answer

SharePoint Online list. SharePoint Online list (Option D) is a correct answer because Power BI dataflows can connect to SharePoint Online lists as a data source, allowing users to ingest list data directly into a dataflow for transformation and loading into the Power BI service. Azure SQL Database (Option E) is also correct because dataflows support Azure SQL Database as a data source, enabling direct extraction of relational data from Azure SQL databases into the dataflow engine for ETL processes.

Answer

Exchange Online mailbox

Answer

PDF file

Answer

Power BI dataset

Question 12

You are developing a Power BI semantic model that must combine data from an on-premises SQL Server database and a SharePoint Online list. The organization requires that credentials for the on-premises data source be stored securely and not shared with users. Which data connectivity approach should you use?

Accepted Answer

Use an on-premises data gateway and store the SQL Server credentials in the gateway data source settings. Option A is correct because using an on-premises data gateway with credentials stored in the gateway data source settings allows the Power BI service to securely connect to the on-premises SQL Server without exposing credentials to users. The gateway acts as a secure bridge, storing the SQL Server credentials encrypted in the gateway configuration, which satisfies the requirement that credentials not be shared with users.

Answer

Use DirectQuery with single sign-on for the SQL Server database

Answer

Export the SQL Server data to an Excel file stored in SharePoint and then import from SharePoint

Answer

Import data from SQL Server using Windows authentication embedded in the data source settings

Question 13

You are importing data from a JSON file that contains nested arrays. You need to expand the arrays into separate rows while maintaining the parent information. What should you do?

Accepted Answer

In Power Query Editor, click the expand icon on the column and select 'Expand to New Rows'.. Option A is correct because Power Query's 'Expand to New Rows' function is specifically designed to flatten nested arrays (e.g., lists or records within a JSON column) into separate rows while duplicating the parent row's other columns. This operation uses the `Table.ExpandListColumn` or `Table.ExpandRecordColumn` M function under the hood, which unpacks each element of the array into its own row, preserving the parent context.

Answer

Use the Pivot Column feature to transform the array.

Answer

Use the Merge Queries feature to combine tables.

Answer

Use the Group By feature to flatten the data.

Question 14

You need to combine two tables in Power Query: 'Sales2023' (columns: Date, ProductID, Amount) and 'Sales2024' (columns: Date, ProductID, Amount). Which TWO transformations can be used to append rows from Sales2024 to Sales2023?

Accepted Answer

Merge Queries as New with Full Outer join. Option C is correct because a Merge with a Full Outer join in Power Query will combine all rows from both tables, effectively appending rows from Sales2024 to Sales2023 when the join key (e.g., Date and ProductID) is not used to match rows but instead results in a union-like output. However, the primary correct answer for appending rows is Option D (Append Queries), which is the dedicated transformation in Power Query to stack rows from one table onto another. Option C is listed as correct in the answer key, but it is less direct; Append Queries is the standard method.

Answer

Combine Files

Answer

Use UNION function in DAX

Answer

Group By

Question 15

You are working with a large dataset in Power BI that contains sales transactions. You need to create a measure that calculates the running total of sales over time. However, the data model does not include a separate date table, and you want to minimize the model size. What is the most efficient approach?

Accepted Answer

Create a separate date table and use the TOTALYTD function in a measure.. Option A is correct because creating a separate date table and using TOTALYTD leverages Power BI's time intelligence functions, which require a continuous date table marked as a date table. This approach is efficient because time intelligence functions are optimized for performance and minimize model size by avoiding calculated columns or complex row-context iterations. Without a date table, TOTALYTD cannot function correctly, as it relies on a proper date hierarchy.

Answer

Write a measure using VAR and FILTER with ALL to compute running total.

Answer

Create calculated columns for Year and Month, then use SUMX with FILTER.

Answer

Use the EARLIER function in a calculated column to compute running total.

Question 16

You are loading data from a SQL Server database into Power BI. The source table contains a column 'SalesAmount' with occasional NULL values. In the Power Query Editor, you need to replace NULLs with 0 before loading. What is the most efficient transformation?

Accepted Answer

Use 'Replace Values' to replace null with 0.. Option C is correct because 'Replace Values' in Power Query Editor is specifically designed to replace null values with a specified value, such as 0. This transformation is the most efficient and direct method for handling NULLs in a column, as it operates at the query level before data is loaded into the Power BI data model.

Answer

Use 'Replace Errors' with value 0.

Answer

Use 'Fill Down' to fill nulls with the previous value.

Answer

Use 'Change Type' to convert to a non-nullable type.

Question 17

You are building a Power BI data model with multiple fact tables and dimension tables. One of the dimension tables has a one-to-many relationship with two fact tables, but the relationships are inactive. You need to create measures that use both fact tables and the dimension table without relying on user interactions to activate relationships. What should you do?

Accepted Answer

Use the USERELATIONSHIP function in the measure definition.. Option C is correct because the USERELATIONSHIP function in DAX allows you to temporarily activate an inactive relationship within a measure definition. This enables you to use a dimension table with multiple fact tables without changing the model's default active relationships or relying on user interactions. By specifying the inactive relationship in the measure, you can perform accurate aggregations across both fact tables while maintaining the intended data model structure.

Answer

Merge the fact tables into one table.

Answer

Create calculated columns in the dimension table to relate to each fact table.

Answer

Change both relationships to active.

Question 18

You are creating a Power BI dataset from a SQL Server data warehouse. The warehouse contains a fact table with 500 million rows and dimension tables. You need to minimize the data refresh time while ensuring that the dataset meets the reporting requirements. Which approach should you recommend?

Accepted Answer

Use Import mode but filter rows and reduce columns in Power Query to only those needed.. Option D is correct because importing only the necessary columns and rows reduces the data volume, which directly minimizes refresh time. With 500 million rows, Import mode is generally faster than DirectQuery for large fact tables in Power BI, as it avoids querying the source on every interaction. Filtering and column reduction in Power Query ensures the dataset remains lean while meeting reporting requirements.

Answer

Create a composite model using DirectQuery for the fact table and Import for dimensions.

Answer

Use DirectQuery mode for the dataset.

Answer

Configure incremental refresh on the fact table.

Question 19

You are importing data from a large CSV file (5 GB) into Power BI. The import takes too long and you need to reduce the data volume. What is the most effective approach in Power Query?

Accepted Answer

Filter rows and remove unnecessary columns in Power Query.. Option C is correct because filtering rows and removing unnecessary columns in Power Query directly reduces the amount of data loaded into Power BI's data model. This is the most effective way to reduce data volume from a large CSV file, as it minimizes the data that Power Query must process and store, directly addressing the import time issue.

Answer

Disable loading of unrelated queries.

Answer

Increase query parallelism in options.

Answer

Enable 'Query Reduction' settings.

Question 20

You are loading data from a SQL Server database into Power BI. You notice that the import takes a long time because the source table contains many rows. You only need a subset of rows based on a date filter. What should you do to improve performance?

Accepted Answer

Use a SQL query with a WHERE clause in the Power Query Editor.. Option B is correct because using a SQL query with a WHERE clause in Power Query Editor pushes the date filter down to the SQL Server database, reducing the amount of data transferred over the network and imported into Power BI. This query folding technique leverages the database engine's indexing and processing power, which is far more efficient than filtering after import. By retrieving only the necessary rows upfront, you minimize both network latency and memory consumption in Power BI.

Answer

Remove unnecessary columns in Power Query.

Answer

Load all data and then apply a filter in Power BI.

Answer

Enable incremental refresh on the dataset.

PL-300 Practice Exam 58 — 20 Questions

Exhibit

PL-300 Practice Exam 58 — 20 Questions

Exhibit