FILTER function in Power BI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the FILTER function do in Power BI?

FILTER returns a table that contains only the rows that meet a specified condition.

beginner

Write the syntax of the FILTER function.

FILTER(<table>, <condition>)

Where <table> is the table to filter and <condition> is the logical test applied to each row.

intermediate

Can FILTER be used inside a measure in Power BI?

Yes, FILTER is often used inside measures to create dynamic calculations based on filtered data.

beginner

What type of output does FILTER return?

FILTER returns a table, not a single value. This table can be used as input for other functions.

beginner

Example: How to filter the 'Sales' table to only include rows where 'Amount' is greater than 100?

FILTER(Sales, Sales[Amount] > 100)

What does the FILTER function return in Power BI?

A A filtered table

B A single number

C A text string

D A chart

FILTER returns a table containing only rows that meet the condition.

Which of these is the correct syntax for FILTER?

A FILTER(<table>)

B FILTER(<condition>, <table>)

C FILTER(<condition>)

D FILTER(<table>, <condition>)

FILTER requires a table first, then a condition to filter rows.

Can FILTER be used inside a measure to calculate values dynamically?

A Yes

B No

C Only in calculated columns

D Only in visuals

FILTER is commonly used inside measures for dynamic calculations.

If you want to filter rows where Sales[Quantity] is less than 50, which FILTER expression is correct?

A FILTER(Sales, Sales[Quantity] > 50)

B FILTER(Sales, Sales[Quantity] < 50)

C FILTER(Sales[Quantity] < 50)

D FILTER(<50, Sales)

The correct syntax is FILTER(table, condition).

What happens if FILTER condition matches no rows?

A Returns the whole table

B Returns an error

C Returns an empty table

D Returns zero

FILTER returns an empty table if no rows meet the condition.

Explain how the FILTER function works and give a simple example.

Think about how you pick only certain rows from a list based on a rule.

Describe a scenario where using FILTER inside a measure would be helpful.

Imagine you want to calculate totals but only for some specific data.

Practice

1. What does the FILTER function do in Power BI?

easy

A. It calculates the sum of a column.

B. It creates a new table by combining two tables.

C. It selects rows from a table that meet a specific condition.

D. It changes the data type of a column.

Solution

1. Step 1: Understand the purpose of FILTER

   The FILTER function is designed to pick rows from a table based on a condition you specify.

2. Step 2: Compare with other options

   Options B, C, and D describe different functions like JOIN, SUM, or data type changes, which FILTER does not do.

3. Final Answer:

   It selects rows from a table that meet a specific condition. -> Option C

4. Quick Check:

   FILTER picks rows = A [OK]

Hint: FILTER always returns rows matching a condition [OK]

Common Mistakes:

• Thinking FILTER changes data types
• Confusing FILTER with aggregation functions
• Assuming FILTER combines tables

2. Which of the following is the correct syntax for the FILTER function in DAX?

easy

A. FILTER(Table; Condition)

B. FILTER(Table, Condition)

C. FILTER(Condition, Table)

D. FILTER[Table, Condition]

Solution

1. Step 1: Recall FILTER syntax

   The correct syntax is FILTER(table, condition) where the first argument is the table and the second is the condition.

2. Step 2: Check each option

   FILTER(Table, Condition) matches the correct syntax. FILTER(Condition, Table) reverses arguments. FILTER(Table; Condition) uses a semicolon instead of a comma. FILTER[Table, Condition] uses brackets incorrectly.

3. Final Answer:

   FILTER(Table, Condition) -> Option B

4. Quick Check:

   FILTER syntax = FILTER(table, condition) [OK]

Hint: Table first, condition second in FILTER [OK]

Common Mistakes:

• Swapping table and condition order
• Using semicolons instead of commas
• Using brackets instead of parentheses

3. Given the table Sales with a column Amount, what does this DAX expression return?

FILTER(Sales, Sales[Amount] > 100)

medium

A. All rows where Amount is greater than 100

B. A single value showing the max Amount

C. Sum of Amount values greater than 100

D. All rows where Amount is less than or equal to 100

Solution

1. Step 1: Analyze the FILTER condition

   The condition Sales[Amount] > 100 means only rows with Amount greater than 100 are kept.

2. Step 2: Understand FILTER output

   FILTER returns a table with rows meeting the condition, not sums or single values.

3. Final Answer:

   All rows where Amount is greater than 100 -> Option A

4. Quick Check:

   FILTER with Amount > 100 returns matching rows [OK]

Hint: FILTER returns rows matching condition, not aggregates [OK]

Common Mistakes:

• Thinking FILTER returns sums or single values
• Confusing > with <=
• Assuming FILTER changes data

4. Identify the error in this DAX expression:

FILTER(Sales, Sales[Amount] => 50)

medium

A. The comparison operator => is invalid

B. The table name is incorrect

C. Missing closing parenthesis

D. FILTER requires three arguments

Solution

1. Step 1: Check the comparison operator

   The operator => is not valid in DAX; the correct operator for 'greater than or equal' is >=.

2. Step 2: Verify other parts

   The table name Sales is correct, parentheses are balanced, and FILTER takes two arguments, so no other errors.

3. Final Answer:

   The comparison operator => is invalid -> Option A

4. Quick Check:

   Use >=, not => for comparisons [OK]

Hint: Use >= for 'greater or equal', not => [OK]

Common Mistakes:

• Using => instead of >=
• Assuming FILTER needs more arguments
• Ignoring syntax errors in operators

5. You want to calculate the total sales amount only for products in the 'Electronics' category. Which DAX measure correctly uses FILTER to do this?

Options:
A) TotalElectronics = CALCULATE(SUM(Sales[Amount]), FILTER(Sales, Sales[Category] = "Electronics"))
B) TotalElectronics = SUM(FILTER(Sales, Sales[Category] = "Electronics"))
C) TotalElectronics = FILTER(Sales, Sales[Category] = "Electronics")
D) TotalElectronics = CALCULATE(FILTER(Sales, Sales[Category] = "Electronics"), SUM(Sales[Amount]))

hard

A. TotalElectronics = CALCULATE(FILTER(Sales, Sales[Category] = "Electronics"), SUM(Sales[Amount]))

B. TotalElectronics = SUM(FILTER(Sales, Sales[Category] = "Electronics"))

C. TotalElectronics = FILTER(Sales, Sales[Category] = "Electronics")

D. TotalElectronics = CALCULATE(SUM(Sales[Amount]), FILTER(Sales, Sales[Category] = "Electronics"))

Solution

1. Step 1: Understand the goal

   You want the sum of Amount but only for rows where Category is 'Electronics'.

2. Step 2: Analyze each option

   TotalElectronics = CALCULATE(SUM(Sales[Amount]), FILTER(Sales, Sales[Category] = "Electronics")) uses CALCULATE with SUM and FILTER correctly to filter rows before summing.
   TotalElectronics = SUM(FILTER(Sales, Sales[Category] = "Electronics")) tries to SUM a table, which is invalid.
   TotalElectronics = FILTER(Sales, Sales[Category] = "Electronics") returns a table, not a sum.
   TotalElectronics = CALCULATE(FILTER(Sales, Sales[Category] = "Electronics"), SUM(Sales[Amount])) misuses CALCULATE arguments order.

3. Final Answer:

   TotalElectronics = CALCULATE(SUM(Sales[Amount]), FILTER(Sales, Sales[Category] = "Electronics")) -> Option D

4. Quick Check:

   Use CALCULATE with FILTER for conditional sums [OK]

Hint: Use CALCULATE with FILTER to sum filtered rows [OK]

Common Mistakes:

• Trying to SUM a filtered table directly
• Returning a table instead of a number
• Incorrect argument order in CALCULATE