Tableau-Desktop-Found Connecting to and Preparing Data Practice Question
When connecting to an Excel file with multiple sheets, you need to combine the data into a single table structure using the Data Source tab. Which feature allows you to stack these sheets vertically if they share the same column headers?
⚠ Common exam trap
Candidates often confuse 'Union' with 'Join'. They try to perform a join to stack data, which results in columns being added horizontally rather than rows being appended vertically.
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
✓
Union
The Union feature in Tableau is designed specifically to combine tables with the same structure by appending rows from one table to the bottom of another. This is critical for users who receive periodic extracts—such as monthly sales reports—that need to be analyzed as a single continuous time series without manually merging files in Excel before connecting to Tableau.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Join
Why it's wrong here
Joining combines tables horizontally by adding columns based on a shared key or field. It does not stack data vertically, meaning it cannot aggregate rows from multiple sheets unless they represent related entities, which is not the intended purpose of consolidating identically structured monthly reports.
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Relationship
Why it's wrong here
Relationships are dynamic, table-level associations that maintain separate tables in the logical layer. They allow for context-aware aggregation but do not physically merge the data rows into a single table structure, making them unsuitable for stacking identical data sheets into one cohesive data source.
- ✓
Union
Why this is correct
A union is the standard method for stacking data from multiple sheets or files that share identical column headers. By performing a union, Tableau creates a unified table containing all rows from each sheet, enabling comprehensive analysis across the entire dataset without requiring manual file manipulation.
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Data Blending
Why it's wrong here
Data blending is a technique used to query data from different data sources on a single sheet. It does not perform a physical union of the underlying data and is generally less performant than using a native union or relationship when working with homogenous data structures.
About these practice questions
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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.