Column operations (rename, remove, reorder) in Power BI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to rename the column 'Sales' to 'Total Sales' in Power Query.

Power BI

Table.RenameColumns(Source, [1])

Drag options to blanks, or click blank then click option'

A{{"Sales", "Sales Total"}}

B{{"Sales", "Total Sales"}}

C{{"Amount", "Total Sales"}}

D{{"Sales", "Revenue"}}

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong column names in the list.

Not using a list of lists (missing brackets).

Swapping old and new names.

In Power Query, to rename a column, you use Table.RenameColumns with a list of pairs: the old name and the new name. Here, we rename 'Sales' to 'Total Sales'.

2fill in blank

medium

Complete the code to remove the column 'Discount' from the table in Power Query.

Power BI

Table.RemoveColumns(Source, [1])

Drag options to blanks, or click blank then click option'

A{"Discounted"}

B{"discount"}

C{"Discount"}

D{"Discounts"}

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect column name or wrong case.

Not using a list (missing brackets).

The Table.RemoveColumns function removes columns by name. The column name must match exactly, including case. Here, 'Discount' is the correct column to remove.

3fill in blank

hard

Fix the error in the code to reorder columns so that 'Date' comes first in Power Query.

Power BI

Table.ReorderColumns(Source, [1])

Drag options to blanks, or click blank then click option'

A{"Date", "Sales", "Region"}

B{Date, Sales, Region}

C{"Sales", "Region", "Date"}

D{"date", "sales", "region"}

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around column names.

Incorrect order of columns.

Wrong case in column names.

The Table.ReorderColumns function requires a list of column names as text strings in the desired order. The column names must be exact and enclosed in quotes.

4fill in blank

hard

Fill both blanks to rename 'Profit' to 'Net Profit' and remove the 'Cost' column in Power Query.

Power BI

let Renamed = Table.RenameColumns(Source, [1]), Removed = Table.RemoveColumns(Renamed, [2]) in Removed

Drag options to blanks, or click blank then click option'

A{{"Profit", "Net Profit"}}

B{"Cost"}

C{"cost"}

D{{"Cost", "Expense"}}

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping rename and remove steps.

Using wrong column names or case.

Not using lists properly.

First, rename the 'Profit' column to 'Net Profit' using Table.RenameColumns. Then remove the 'Cost' column with Table.RemoveColumns. Both functions require lists with exact column names.

5fill in blank

hard

Fill all three blanks to reorder columns to ['Region', 'Date', 'Sales'], rename 'Sales' to 'Total Sales', and remove 'Discount' in Power Query.

Power BI

let Reordered = Table.ReorderColumns(Source, [1]), Renamed = Table.RenameColumns(Reordered, [2]), Removed = Table.RemoveColumns(Renamed, [3]) in Removed

Drag options to blanks, or click blank then click option'

A{"Region", "Date", "Sales"}

B{{"Sales", "Total Sales"}}

C{"Discount"}

D{"Date", "Region", "Sales"}

Attempts:

3 left

💡 Hint

Common Mistakes

Incorrect column order in reorder step.

Wrong column names or case in rename or remove steps.

Mixing up list formats.

First, reorder columns to have 'Region', 'Date', and 'Sales' in that order. Then rename 'Sales' to 'Total Sales'. Finally, remove the 'Discount' column. Each step uses the correct function with proper lists.

Practice

1.

What is the main purpose of renaming columns in Power BI's Power Query Editor?

easy

A. To give columns clear, meaningful names for easier understanding

B. To delete unwanted data from the table

C. To change the data type of the column

D. To create new calculated columns

Solution

1. Step 1: Understand column renaming

   Renaming columns means changing their names to something more descriptive or meaningful.

2. Step 2: Purpose of renaming

   This helps users and report viewers understand what data the column holds without confusion.

3. Final Answer:

   To give columns clear, meaningful names for easier understanding -> Option A

4. Quick Check:

   Renaming improves clarity = To give columns clear, meaningful names for easier understanding [OK]

Hint: Rename columns to clear names before loading data [OK]

Common Mistakes:

• Confusing renaming with deleting columns
• Thinking renaming changes data values
• Mixing renaming with changing data types

2.

Which of the following is the correct way to remove a column named SalesAmount in Power Query Editor?

easy

A. Rename the column to Remove

B. Double-click the SalesAmount column and type Delete

C. Drag the SalesAmount column to the end of the table

D. Right-click the SalesAmount column header and select Remove

Solution

1. Step 1: Identify how to remove columns in Power Query

   Removing a column is done by right-clicking its header and choosing the remove option.

2. Step 2: Check each option

   Only Right-click the SalesAmount column header and select Remove correctly describes this action. Double-clicking edits names, renaming doesn't remove, and dragging reorders columns.

3. Final Answer:

   Right-click the SalesAmount column header and select Remove -> Option D

4. Quick Check:

   Remove column = Right-click + Remove [OK]

Hint: Right-click column header to remove it quickly [OK]

Common Mistakes:

• Trying to delete by renaming
• Assuming double-click deletes column
• Dragging column removes it

3.

Given a table with columns Product, Sales, and Date, what will be the new column order after applying this step in Power Query Editor?

Table.ReorderColumns(Source, {"Date", "Product", "Sales"})

medium

A. ["Sales", "Date", "Product"]

B. ["Product", "Sales", "Date"]

C. ["Date", "Product", "Sales"]

D. ["Sales", "Product", "Date"]

Solution

1. Step 1: Understand Table.ReorderColumns function

   This function changes the order of columns to the list provided in the second argument.

2. Step 2: Apply the given list

   The list is ["Date", "Product", "Sales"], so the columns will be reordered exactly in that sequence.

3. Final Answer:

   ["Date", "Product", "Sales"] -> Option C

4. Quick Check:

   ReorderColumns list = new order [OK]

Hint: ReorderColumns sets columns exactly as listed [OK]

Common Mistakes:

• Assuming original order stays
• Mixing up column names order
• Ignoring the reorder list

4.

You tried to rename a column in Power Query Editor but got an error. Which of these is the most likely cause?

Table.RenameColumns(Source, {"Sales", "Revenue"})

medium

A. The source table must be empty before renaming

B. The rename list should be a list of lists like {{"Sales", "Revenue"}}

C. The new name must be numeric

D. You cannot rename columns in Power Query Editor

Solution

1. Step 1: Check syntax for Table.RenameColumns

   The function expects a list of pairs (old name, new name) inside another list, like {{"Old", "New"}}.

2. Step 2: Identify error cause

   The code uses a single pair without the outer list, causing a syntax error.

3. Final Answer:

   The rename list should be a list of lists like {{"Sales", "Revenue"}} -> Option B

4. Quick Check:

   RenameColumns needs list of lists [OK]

Hint: Use double braces {{old, new}} to rename columns [OK]

Common Mistakes:

• Using single list instead of list of lists
• Thinking renaming is not allowed
• Expecting numeric names only

5.

You have a table with columns ID, Name, Age, and Salary. You want to remove Age, rename Salary to Income, and reorder columns so Name comes first. Which sequence of Power Query steps is correct?

hard

A. Remove Age, Rename Salary to Income, Reorder columns to ["Name", "ID", "Income"]

B. Rename Salary to Income, Remove Age, Reorder columns to ["ID", "Name", "Income"]

C. Reorder columns to ["ID", "Name", "Salary", "Age"], Remove Age, Rename Salary to Income

D. Remove Name, Rename Age to Income, Reorder columns to ["ID", "Salary"]

Solution

1. Step 1: Remove the Age column

   First, remove the unwanted Age column to exclude it from the table.

2. Step 2: Rename Salary to Income

   Next, rename the Salary column to Income for clarity.

3. Step 3: Reorder columns with Name first

   Finally, reorder columns so Name is first, followed by ID and Income.

4. Final Answer:

   Remove Age, Rename Salary to Income, Reorder columns to ["Name", "ID", "Income"] -> Option A

5. Quick Check:

   Remove, Rename, Reorder in that order [OK]

Hint: Remove unwanted, rename needed, reorder last [OK]

Common Mistakes:

• Reordering before removing columns
• Renaming wrong columns
• Removing needed columns by mistake