VALUES and DISTINCT in Power BI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the VALUES function do in Power BI DAX?

VALUES returns a one-column table that contains the distinct values from the specified column, including blank if present.

intermediate

How is DISTINCT different from VALUES in DAX?

DISTINCT returns a one-column table of unique values from a column but excludes blanks, while VALUES includes blanks.

intermediate

Can VALUES return multiple columns?

Yes, when used on a table, VALUES returns all distinct rows with all columns, not just one column.

beginner

What happens if VALUES is used on a column with no data?

VALUES returns an empty table with no rows.

intermediate

Why might you choose DISTINCT over VALUES in a measure?

You might choose DISTINCT to exclude blank values when you want only actual data values without blanks.

Which function returns distinct values including blanks?

A VALUES

B DISTINCT

C FILTER

D SUMMARIZE

VALUES returns distinct values including blanks, while DISTINCT excludes blanks.

What does DISTINCT return?

A Unique values excluding blanks

B All values including duplicates

C Only blank values

D All rows including duplicates

DISTINCT returns unique values from a column and excludes blanks.

Which function can return multiple columns with distinct rows?

A SUM

B DISTINCT

C CALCULATE

D VALUES

VALUES can return distinct rows with multiple columns when used on a table.

If you want to exclude blank values from your distinct list, which function should you use?

A VALUES

B DISTINCT

C ALL

D RELATED

DISTINCT excludes blank values, so it is the right choice.

What type of output do both VALUES and DISTINCT produce?

A Single scalar value

B Boolean true/false

C Table of distinct values

D Aggregated sum

Both functions return a table of distinct values from a column.

Explain in your own words the difference between VALUES and DISTINCT in Power BI DAX.

Think about how blanks are treated and the output type.

Describe a real-life scenario where you would use VALUES instead of DISTINCT.

Consider when blanks are meaningful in your data.

Practice

1. What is the main difference between the DAX functions VALUES and DISTINCT?

easy

A. VALUES returns unique values including blanks, DISTINCT returns unique values excluding blanks.

B. VALUES returns unique values and blanks, DISTINCT returns unique values including blanks.

C. VALUES returns unique values excluding blanks, DISTINCT excludes blanks.

D. VALUES and DISTINCT are exactly the same in all cases.

Solution

1. Step 1: Understand VALUES behavior

   VALUES returns unique values from a column and includes blank values if they exist.

2. Step 2: Understand DISTINCT behavior

   DISTINCT returns unique values but excludes blank values from the result.

3. Final Answer:

   VALUES includes blanks, DISTINCT excludes blanks -> Option A

4. Quick Check:

   VALUES includes blanks, DISTINCT excludes blanks [OK]

Hint: Remember: VALUES keeps blanks, DISTINCT drops them [OK]

Common Mistakes:

• Thinking VALUES and DISTINCT always return the same results
• Assuming DISTINCT includes blanks
• Confusing the behavior of blank values in both functions

2. Which of the following is the correct syntax to get unique values from the column Product[Category] using DISTINCT?

easy

A. DISTINCT(Product[Category])

B. DISTINCT(Product.Category)

C. VALUES(Product[Category])

D. VALUES(Product.Category)

Solution

1. Step 1: Check correct column reference syntax

   In DAX, columns are referenced with table name and column name inside square brackets, like Product[Category].

2. Step 2: Check function syntax

   Both VALUES and DISTINCT take a column reference in parentheses. The correct syntax is DISTINCT(Product[Category]).

3. Final Answer:

   DISTINCT(Product[Category]) -> Option A

4. Quick Check:

   Correct syntax uses square brackets and function call [OK]

Hint: Use square brackets for columns inside functions [OK]

Common Mistakes:

• Using dot notation instead of square brackets
• Missing parentheses after function name
• Using incorrect column references

3. Given a table Sales with a column CustomerID containing values [1, 2, 2, 3, BLANK, 3], what will be the result of COUNTROWS(VALUES(Sales[CustomerID]))?

medium

A. 6

B. 3

C. 4

D. 5

Solution

1. Step 1: Identify unique values including blanks

   The unique values in CustomerID are 1, 2, 3, and BLANK. That is 4 unique values.

2. Step 2: Apply COUNTROWS on VALUES

   VALUES returns unique values including blanks, so COUNTROWS counts 4 rows.

3. Final Answer:

   4 -> Option C

4. Quick Check:

   Unique values including blank = 4 [OK]

Hint: VALUES includes blanks, so count them too [OK]

Common Mistakes:

• Ignoring blank values in count
• Counting duplicates multiple times
• Confusing DISTINCT behavior here

4. You wrote this DAX measure: UniqueProducts = DISTINCT(Product[ProductName]). When you use it in a card visual, it shows an error. What is the problem?

medium

A. The column name is incorrect; it should be ProductName[Product].

B. DISTINCT returns a table, but card visuals need a single value.

C. DISTINCT cannot be used in measures, only in calculated columns.

D. You need to wrap DISTINCT with SUM to get a number.

Solution

1. Step 1: Understand what DISTINCT returns

   DISTINCT returns a table of unique values, not a single number or scalar value.

2. Step 2: Understand card visual requirements

   Card visuals require a single scalar value, like a number or text, not a table.

3. Final Answer:

   DISTINCT returns a table, but card visuals need a single value. -> Option B

4. Quick Check:

   DISTINCT returns table, card needs scalar [OK]

Hint: DISTINCT returns tables; use aggregation for single values [OK]

Common Mistakes:

• Using DISTINCT directly in measures for visuals needing scalars
• Incorrect column references
• Thinking DISTINCT returns a number

5. You want to create a slicer that shows only unique non-blank customer names from the Customers[Name] column. Which DAX expression should you use to create a calculated table for this slicer?

hard

A. CustomerNames = FILTER(DISTINCT(Customers[Name]), NOT(ISBLANK(Customers[Name])))

B. CustomerNames = VALUES(Customers[Name])

C. CustomerNames = FILTER(VALUES(Customers[Name]), NOT(ISBLANK(Customers[Name])))

D. CustomerNames = DISTINCT(Customers[Name])

Solution

1. Step 1: Understand the need to exclude blanks

   Both VALUES and DISTINCT return unique values, but VALUES includes blanks while DISTINCT excludes them.

2. Step 2: Choose function and filter blanks

   DISTINCT returns unique values excluding blanks, which is perfect for a slicer.

3. Step 3: Compare options

   CustomerNames = DISTINCT(Customers[Name]) directly provides unique non-blank names without needing extra filtering.

4. Final Answer:

   CustomerNames = DISTINCT(Customers[Name]) -> Option D

5. Quick Check:

   DISTINCT excludes blanks for clean slicer [OK]

Hint: DISTINCT excludes blanks automatically [OK]

Common Mistakes:

• Using VALUES without filtering blanks
• Assuming DISTINCT includes blanks
• Using incorrect column references in FILTER conditions