Tableau-Desktop-Found Exploring and Analyzing Data Practice Question
You are creating a report to track monthly revenue. You notice that some months have missing data points in the database. What is the most effective way to ensure these months appear on the axis with a value of zero?
⚠ Common exam trap
Candidates often enable 'Show Missing Values' but forget that this only creates the visual header, not the actual numeric value, leaving the data as null instead of zero.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable 'Show Missing Values' and use ZN().
Handling missing data is a common challenge in time-series analysis. By enabling 'Show Missing Values' on the date pill, Tableau generates the missing temporal headers. However, simply showing the headers does not create data points. Using the ZN() function on the measure ensures that these newly generated time buckets are treated as zero rather than null, preventing gaps in line charts and ensuring accurate cumulative calculations like running totals.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use the ZN() function on the measure.
Why it's wrong here
Using ZN() alone is insufficient because it only handles existing nulls in the database. It cannot create missing months that are not present in the original dataset. You must first generate the missing headers using 'Show Missing Values' before ZN() can effectively convert the generated nulls into zero values.
- ✗
Filter out nulls using a calculated field.
Why it's wrong here
Filtering out nulls will remove the months entirely from the view, which is the opposite of the desired result. The goal is to display the missing months as zero, not to exclude them from the analysis. Filtering would result in gaps in the line chart, which compromises data integrity.
- ✓
Enable 'Show Missing Values' and use ZN().
Why this is correct
Enabling 'Show Missing Values' creates the necessary placeholders for missing dates. Once these placeholders exist, they contain null values. Applying the ZN() function to the measure converts these nulls into zero, resulting in a continuous line chart that correctly reflects zero revenue for months without recorded transactions.
- ✗
Join the dataset to a calendar table.
Why it's wrong here
While joining to a calendar table is a valid advanced solution for sparse data, it is unnecessarily complex for Tableau. Tableau's built-in 'Show Missing Values' feature is specifically designed for this purpose, making manual data preparation or complex joins redundant for basic time-series visualization needs in most scenarios.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Tableau (Salesforce) exam blueprint
This Tableau-Desktop-Found practice question is part of Courseiva's free Tableau (Salesforce) certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the Tableau-Desktop-Found exam.