PL-300 Practice Exam 4 — 20 Questions

Question 1

A user reports that a Power BI report is not refreshing data from a SQL Server database. The dataset uses Import mode. The gateway cluster shows all gateways are online. What is the most likely cause?

Accepted Answer

The data source credentials are incorrect or expired.. In Import mode, Power BI caches data and refreshes it on a schedule using stored credentials. If those credentials expire or become invalid, the refresh fails even though the gateway cluster shows as online. The gateway being online only indicates network connectivity, not that the stored credentials are still valid for the SQL Server database.

Answer

The report is using a scheduled refresh with a conflicting time.

Answer

The gateway version is incompatible with the SQL Server version.

Answer

The dataset uses DirectQuery mode which requires a live connection.

Question 2

Drag and drop the steps to create a relationship between two tables in Power BI Desktop into the correct order.

Accepted Answer

Open Model view, drag a column from one table to a column in another table, configure cardinality and cross-filter direction in the Edit Relationship dialog, then click OK.. Relationships are created by dragging columns between tables in the Model view, then confirming settings like cardinality.

Answer

Open Model view, click on the table to select it, then click on the 'Create Relationship' button in the ribbon, then select the columns from a dropdown menu, then click OK.

Answer

Open Model view, drag a column from one table to the other table header, then in the dialog that appears, choose the cardinality, then click OK.

Answer

Open Model view, configure cardinality and cross-filter direction in the Edit Relationship dialog, then drag a column from one table to a column in another table, then click OK.

Question 3

You are preparing a data model that uses a date table. You need to ensure that the date table includes all dates from January 1, 2020 to December 31, 2025. What is the most efficient way to create this date table in Power Query?

Accepted Answer

Use the 'List.Dates' function to generate the date range.. The 'List.Dates' function in Power Query M is the most efficient way to generate a contiguous range of dates directly within the query editor, without external dependencies. It creates a list of dates from a start date to an end date using a specified step (e.g., #duration(1,0,0,0) for one day), which can then be converted into a table. This approach is lightweight, fully self-contained, and avoids the overhead of importing external files or using DAX functions that are not native to Power Query.

Answer

Import a date table from an Excel file.

Answer

Use the 'Calendar' function in Power Query M.

Answer

Use the 'CALENDAR' DAX function in Power Query.

Question 4

What is the most likely cause of the error in the DAX query shown in the exhibit?

Accepted Answer

The [Sales Amount] measure is returning multiple values or is not a valid scalar measure.. The error 'A single value for column 'Sales Amount' in table 'Sales' cannot be determined' occurs because the [Sales Amount] measure is being used in a context that expects a scalar value, but the measure is defined to return multiple values (e.g., using SUMX over a table that returns multiple rows without proper aggregation). In DAX, measures used in EVALUATE statements must return a single scalar value; if the measure is not properly aggregated or contains a many-to-many relationship, it can produce multiple values, causing this error.

Answer

There is no relationship between Date and Product tables.

Answer

The SUMMARIZECOLUMNS function does not support multiple group-by columns.

Answer

The ORDER BY clause is not allowed in EVALUATE statements.

Question 5

You are modeling data from multiple sources: a SQL Server database for sales, an Excel file for budget, and a SharePoint list for product targets. You need to combine these into a single Power BI report. What is the recommended approach for handling data refresh?

Accepted Answer

Use Power Query to combine data from all sources into a single dataset, then schedule a daily refresh in the Power BI service.. Power Query (Get Data) in Power BI Desktop is designed to connect to and combine data from multiple heterogeneous sources—SQL Server, Excel, and SharePoint—into a single dataset. After publishing to the Power BI service, you can configure a scheduled refresh (via an on-premises data gateway for on-premises sources) to keep the dataset up to date automatically, which is the recommended approach for recurring refreshes.

Answer

Import each source into separate Power BI Desktop files and manually update.

Answer

Use Excel Online as the single source and import all data into it first.

Answer

Create separate datasets for each source and use composite models with DirectQuery.

Question 6

Which TWO are valid methods to handle null values in Power Query? (Choose two.)

Accepted Answer

Use the 'Fill Down' or 'Fill Up' option to propagate non-null values into null cells.. 'Fill Down' and 'Fill Up' propagate the last non-null value into adjacent null cells. Option C is correct because 'Replace Values' can replace nulls with a default value. Option B is incorrect: 'Remove Blank Rows' removes rows where all cells are blank, not rows with nulls in specific columns. Option D is not a direct method for handling nulls; merging may introduce new data but does not handle existing nulls. Option E is invalid because changing to a non-nullable type causes errors.

Answer

Remove rows that contain null values using the 'Remove Rows' > 'Remove Blank Rows' option.

Answer

Merge the table with another table that has no nulls.

Answer

Change the data type of the column to a non-nullable type.

Question 7

You are preparing data for a Power BI report. The source data contains a column 'FullName' with values like 'John Doe'. You need to split this column into 'FirstName' and 'LastName' using Power Query. The transformation should be repeatable and not dependent on the number of spaces. What is the best approach?

Accepted Answer

Use 'Split Column by Delimiter' and choose 'Right-most delimiter'.. Using 'Split Column by Delimiter' with 'Right-most delimiter' ensures that the split occurs at the last space in the FullName column, which reliably separates the first name from the last name even if there are multiple spaces (e.g., 'John Michael Doe' would yield 'John Michael' as FirstName and 'Doe' as LastName). This approach is repeatable and does not depend on a fixed number of spaces, making it robust for varying name formats.

Answer

Use 'Split Column by Number of Characters' with a fixed position.

Answer

Use 'Replace Values' to replace space with a comma.

Answer

Use 'Extract Text After Delimiter' with a space.

Question 8

You are designing a data model in Power BI that includes a fact table called 'Sales' and dimension tables 'Customer', 'Product', and 'Date'. The 'Sales' table contains columns: 'SalesID', 'CustomerID', 'ProductID', 'DateKey', 'Quantity', and 'Amount'. You need to ensure that the model follows star schema best practices and that filters from the 'Customer' table propagate correctly to the 'Sales' table. What should you do?

Accepted Answer

Create a one-to-many relationship from Customer (one side) to Sales (many side) based on CustomerID.. In a star schema, the dimension table (Customer) should have a one-to-many relationship to the fact table (Sales) based on the common key (CustomerID). This ensures that filters applied to the Customer table propagate correctly to the Sales table, maintaining referential integrity and enabling efficient query performance.

Answer

Merge the Customer and Sales tables into a single flat table.

Answer

Set the cross-filter direction to Both on the relationship between Customer and Sales.

Answer

Create a many-to-many relationship between Customer and Sales using SalesID.

Question 9

You are a data analyst at a utility company. You load a table of meter readings into Power BI Desktop from an Azure SQL Database. The table has columns MeterId, ReadingTimestamp, and Consumption. You discover duplicate rows caused by a known upstream issue where the same reading is sometimes inserted twice with identical values in all three columns. You need to remove these exact duplicate rows in Power Query while keeping one copy of each reading. What should you do?

Accepted Answer

Select all three columns, then use Remove Rows > Remove Duplicates.. Remove Duplicates treats the set of selected columns as the key for comparison. Selecting MeterId, ReadingTimestamp, and Consumption means only rows identical across all three are collapsed, which matches the described upstream duplication. Narrower keys would delete valid readings, and an index column would prevent any matches.

Answer

Add an index column, then use Remove Rows > Remove Duplicates on the index column.

Answer

Group By MeterId, ReadingTimestamp, and Consumption with an All Rows operation, then expand the first row of each group.

Answer

Select the MeterId column only, then use Remove Rows > Remove Duplicates.

Question 10

You are importing data from an Excel workbook that contains multiple sheets. You only need data from the 'Sales' sheet. In Power Query Editor, what should you do to load only that sheet?

Accepted Answer

In the Navigator dialog, select the 'Sales' sheet and click 'Transform Data'.. In Power Query Editor, the Navigator dialog allows you to preview and select specific tables or sheets from a data source before loading. By selecting the 'Sales' sheet and clicking 'Transform Data', you load only that sheet into Power Query Editor for transformation, avoiding unnecessary data. This is the correct and efficient method to import a single sheet from a multi-sheet Excel workbook.

Answer

Load all sheets, then delete the queries for sheets you don't need.

Answer

Use a filter transform to exclude rows from other sheets.

Answer

Select the entire workbook and then filter out other sheets in Power Query.

Question 11

You are a data analyst at a retail company. You have a Power BI semantic model that imports sales data from an Azure SQL Database. The database uses a timestamp column to track transaction time. You need to reduce the data refresh time and ensure that only the last 30 days of data are refreshed during each scheduled refresh. You have already created the necessary parameters rangeStart and rangeEnd in Power Query. What should you do next to implement incremental refresh?

Accepted Answer

In Power BI Desktop, on the model view, select the table and set the incremental refresh policy.. Incremental refresh policies are defined in Power BI Desktop on the model view, not in the service or by simply filtering in Power Query. After creating the rangeStart and rangeEnd parameters, you must select the table in the Model view, open the incremental refresh policy dialog, and configure the policy to filter data based on those parameters, ensuring only the last 30 days are refreshed.

Answer

In the Power BI service, go to the dataset settings and configure the scheduled refresh.

Answer

In Power Query Editor, apply the rangeStart and rangeEnd filters to the data and then close and apply.

Answer

In the Power BI service, create a new refresh schedule and set the incremental refresh period.

Question 12

You need to combine two tables: Sales and Products, where Sales has a ProductID column and Products has a ProductKey column. The tables have a many-to-one relationship. Which Power Query transformation should you use?

Accepted Answer

Merge Queries.. Merge Queries (C) is correct because it performs a join between two tables based on matching columns, which is exactly what is needed to combine Sales and Products using ProductID and ProductKey. This transformation supports many-to-one relationships and allows you to expand related columns from the Products table into the Sales table, enabling further data analysis.

Answer

Group By.

Answer

Append Queries.

Answer

Pivot Column.

Question 13

A company uses Row-Level Security (RLS) in Power BI. They want to ensure that when a manager views the report, they see data for their own region plus any region where a salesperson reports to them. Which RLS approach should you implement?

Accepted Answer

Use a DAX filter that references the USERPRINCIPALNAME() function. Row-Level Security (RLS) in Power BI uses DAX filters that can dynamically evaluate the current user's identity via USERPRINCIPALNAME() or USERNAME(). By creating a DAX rule that checks whether the manager's UPN matches the region manager or if the salesperson's manager UPN equals the current user, you can enforce dynamic, hierarchical data access without hardcoding roles per manager.

Answer

Use Power BI App permissions to restrict data

Answer

Create a static role for each manager and assign users

Answer

Apply RLS at the visual level using bookmarks

Question 14

You are building a Power BI report for a logistics company. The data is stored in a CSV file on a SharePoint Online document library. The CSV file is updated daily with new rows. You need to ensure that the Power BI dataset reflects the latest data every morning at 7:00 AM. The data volume is small, so full refresh is acceptable. You have already published the report to the Power BI service. What should you do to automate the refresh?

Accepted Answer

In the Power BI service, configure a scheduled refresh for the dataset with the desired time.. The Power BI service supports scheduled refresh natively for datasets that connect to cloud data sources like SharePoint Online CSV files. By configuring a scheduled refresh in the dataset settings, you can set it to run daily at 7:00 AM without any additional tools or gateways. This ensures the dataset reflects the latest data from the CSV file each morning.

Answer

Use Power Automate to trigger a refresh via the Power BI REST API every morning.

Answer

Enable incremental refresh for the dataset and set the refresh frequency to daily.

Answer

Install an on-premises data gateway and configure a scheduled refresh.

Question 15

You are preparing data from a CSV file that contains date values in the format 'MM/dd/yyyy'. When you load the file into Power BI Desktop, the dates appear as text. What should you do to ensure the dates are recognized as date data type?

Accepted Answer

Change the column data type to Date in Power Query Editor. Changing the column data type to Date in Power Query Editor forces Power BI to interpret the text values as dates using the current locale settings. Since the CSV file contains dates in 'MM/dd/yyyy' format, Power Query can parse this pattern when the data type is explicitly set to Date, converting the text strings into the Date data type for proper time intelligence and filtering.

Answer

Use 'Replace Values' to replace '/' with '-'

Answer

Split the column by delimiter '/'

Answer

Promote the first row as headers

Question 16

You are designing a data model for a sales analysis report. The source data includes a Sales table with columns: OrderID, CustomerID, ProductID, OrderDate, Quantity, and UnitPrice. You also have a Customers table and a Products table. Which approach best optimizes query performance and storage?

Accepted Answer

Create a star schema with Sales as a fact table and Customers and Products as dimension tables.. A star schema optimizes query performance and storage in Power BI by separating transactional data (Sales fact table) from descriptive attributes (Customers and Products dimension tables). This reduces data duplication, improves compression, and enables efficient aggregations and filter propagation via one-to-many relationships, which is the recommended modeling approach for analytical workloads.

Answer

Create separate fact tables for each dimension.

Answer

Create a single flat table by joining all columns from Sales, Customers, and Products into one table.

Answer

Create a snowflake schema by normalizing Customers into multiple related tables.

Question 17

You are preparing a Power BI dataset that includes a table 'Products' imported from an Excel workbook. The table has a column 'ProductCode' that contains values like 'A100', 'B200', etc. You need to create a new column that extracts the numeric part of the code (e.g., 100, 200) and uses it as an integer. Which Power Query transformation should you use?

Accepted Answer

Add a Custom Column with the formula Text.Select([ProductCode], {"0".."9"}) and change the type to Whole Number.. Using Text.Select with a list of digits extracts only the numeric characters from the code, regardless of the letter prefix. This creates a text column that can then be converted to an integer. Other methods are either too specific to certain prefixes or extract the wrong portion. Text.Select is the most flexible and correct approach.

Answer

Use the Replace Values transformation to replace 'A' and 'B' with an empty string, then change the type.

Answer

Use the Extract transformation and select 'Text Before Delimiter'.

Answer

Use the Split Column transformation by delimiter 'A' and keep the second part.

Question 18

You have a Power BI data model with a 'Date' table that contains continuous dates from January 1, 2020, to December 31, 2025. The 'Sales' table has a relationship with the 'Date' table. You need to create a measure that calculates the total sales for the last 12 months from the current context. Which DAX function should you use?

Accepted Answer

DATESINPERIOD. The DATESINPERIOD function is correct because it returns a contiguous set of dates from a specified start date (the last date in the current context) going back a given number of intervals (12 months). This allows the measure to dynamically calculate total sales for the trailing 12 months relative to any filter context, such as a specific year or month.

Answer

PREVIOUSMONTH

Answer

DATEADD

Answer

SAMEPERIODLASTYEAR

Question 19

You are a data analyst for a financial services company. You have a Power BI dataset that combines data from two sources: a CSV file in SharePoint Online and an on-premises SQL Server database. The CSV file contains exchange rates that are updated daily. The SQL Server database contains transaction data. You need to ensure that the dataset can be refreshed automatically in the Power BI service. The CSV file is updated at 6:00 AM daily, and the SQL Server database is updated continuously. You have already published the report. What should you do to enable automated refresh?

Accepted Answer

Install and configure an on-premises data gateway, then set up a scheduled refresh.. The on-premises SQL Server database requires an on-premises data gateway to bridge the Power BI service with the local network. Even though the CSV file is in SharePoint Online, the dataset combines both sources; the gateway is mandatory for the SQL Server component. Without it, scheduled refresh cannot access the on-premises data, and the dataset will fail to refresh automatically.

Answer

Use Power Automate to refresh the dataset after the CSV is updated.

Answer

Enable incremental refresh for the SQL Server table to reduce refresh time.

Answer

Configure a scheduled refresh in the dataset settings. The gateway is not required because the CSV file is in SharePoint Online.

Question 20

You are a Power BI data analyst for a manufacturing company. You have a report with a line chart showing daily production output over the past year. Users report that the line chart is cluttered and difficult to read due to daily fluctuations. You need to add analytics features to the line chart to help users identify trends and outliers. Which two features should you add? (Choose two.)

Accepted Answer

Trend line. Adding a trend line helps smooth out daily fluctuations and reveals the overall direction of production output. Anomaly detection automatically identifies and highlights unusual data points, making outliers immediately visible. Together, these features make the line chart easier to interpret. Forecast, constant line, and error bars do not directly address the need to identify trends and outliers in historical data.

Answer

Error bars

Answer

Forecast

Answer

Constant line