Tableau Connecting & Preparing Data 2 — Questions and Answers
Question 1: Which Tableau join type returns only the rows that have matching values in both tables?
- Inner join (Correct answer)
- Left join
- Right join
- Full outer join
Correct answer: Inner join
An inner join keeps only rows where the join keys match in both tables.
Question 2: What does a left join return when there is no matching row in the right table?
- The unmatched left rows with null values for right columns (Correct answer)
- Nothing for that row
- An error message
- Only the right table rows
Correct answer: The unmatched left rows with null values for right columns
A left join keeps all left rows and fills right-table columns with null where no match exists.
Question 3: In Tableau, what is the main difference between a join and a relationship (noodle)?
- Relationships are flexible and defer join logic until analysis (Correct answer)
- Joins are only for Excel files
- Relationships merge tables into one fixed table
- There is no functional difference
Correct answer: Relationships are flexible and defer join logic until analysis
Relationships keep tables separate and determine the appropriate join contextually at query time.
Question 4: Which connection mode in Tableau queries the source database directly each time the view is refreshed?
- Live connection (Correct answer)
- Extract connection
- Snapshot mode
- Offline mode
Correct answer: Live connection
A live connection sends queries to the source database in real time.
Question 5: What file format does a Tableau data extract use?
- .hyper (Correct answer)
- .twb
- .csv
- .tde only
Correct answer: .hyper
Modern Tableau extracts use the .hyper file format.
Question 6: A union in Tableau combines tables by doing what?
- Stacking rows from tables with similar structures (Correct answer)
- Adding columns side by side
- Multiplying rows together
- Removing duplicate columns
Correct answer: Stacking rows from tables with similar structures
A union appends rows from multiple tables that share a similar column structure.
Question 7: Which feature lets you automatically union files whose names match a pattern in a folder?
- Wildcard union (Correct answer)
- Cross-database join
- Data blending
- Pivot
Correct answer: Wildcard union
A wildcard union matches multiple files by name pattern and appends them automatically.
Tableau Connecting & Preparing Data 2
Which Tableau join type returns only the rows that have matching values in both tables?