2 Calculated Columns using DAX .docx

Question 1

What is the purpose of Calculated Columns in Power BI?

Answer 1

Add new columns to existing tables based on specific needs

Calculated Columns enhance data analysis by providing additional calculated data points.

Question 2

What formula language is used to create Calculated Columns?

Answer 2

DAX

DAX stands for Data Analysis Expressions, a powerful formula language in Power BI.

Question 3

What is the first step to create a Calculated Column in Power BI?

Answer 3

Access the table view

This step involves navigating to the specific table where the new column will be added.

Question 4

What option must you select to create a new column?

Answer 4

New Column

This option can be accessed through a menu or an icon in Power BI.

Question 5

What must be defined after naming a new column?

Answer 5

DAX formula

The formula defines the calculation that will populate the new column.

Question 6

Fill in the blank: A common example of a calculated column is ‘DaysTakenToShip’, which uses the _______ function.

Answer 6

DATEDIFF

This function calculates the difference between two date columns.

Question 7

What is meant by ‘Row Context’ in Calculated Columns?

Answer 7

Calculated for each row in the table

The DAX formula is evaluated independently for every single row.

Question 8

Why is it important to ensure data types are compatible in DAX formulas?

Answer 8

To achieve the desired outcome

For example, using DATEDIFF requires date type columns.

Question 9

What performance consideration should be taken into account when using Calculated Columns?

Answer 9

Excessive use can impact performance

Calculated Columns are stored in memory, which can affect the overall efficiency of the Power BI model.

Question 10

When might measures be preferred over Calculated Columns?

Answer 10

For aggregations

Measures can be more efficient for certain types of analysis.

Question 11

What types of functions are available in DAX beyond DATEDIFF?

Answer 11

Mathematical, logical, text, and date functions

These functions provide extensive capabilities for data manipulation.

Question 12

What features does the formula bar in Power BI Desktop offer?

Answer 12

IntelliSense and syntax highlighting

These features assist users in writing DAX formulas more effectively.

Question 13

True or False: Error handling functions like IFERROR can be used in Calculated Column formulas.

Answer 13

True

These functions help manage potential errors in the calculations.