Tableau-Desktop-Found Connecting to and Preparing Data Practice Question
You are joining two tables: 'Sales' and 'Targets'. The 'Targets' table has only one row per region, while the 'Sales' table has multiple rows per region. What join type should you use to preserve all sales data while adding target information?
⚠ Common exam trap
Candidates frequently confuse inner joins with left joins, accidentally dropping sales rows that do not have a matching target entry in the secondary table.
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
✓
Left Join
A Left Join is appropriate here because it keeps every row from the primary 'Sales' table and adds matching 'Targets' data where available. Since 'Targets' is at a higher level of aggregation (region level), this join preserves the transaction-level granularity of the 'Sales' table while associating each transaction with its corresponding target for performance comparison. This correctly models the one-to-many relationship often found in business intelligence.
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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Inner Join
Why it's wrong here
An Inner Join would only return rows where a match exists in both tables. If a 'Sales' record doesn't have a matching region in 'Targets', that transaction record would be dropped. This leads to inaccurate sales reporting, as some transactions would be omitted from the final analysis entirely.
- ✓
Left Join
Why this is correct
A Left Join is the correct choice because it includes all rows from the left table ('Sales') and matches the corresponding rows from the right table ('Targets'). This ensures that no sales data is lost while effectively appending the target figures to each record for regional analysis.
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Right Join
Why it's wrong here
A Right Join would prioritize the 'Targets' table. If there are regions in 'Targets' without any sales, those would be included while potentially missing sales data if they were on the left side of the join. It is not the most logical approach for keeping transaction-level data intact.
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Full Outer Join
Why it's wrong here
A Full Outer Join would keep all records from both tables, resulting in numerous null values for targets in regions where sales exist or sales in regions where targets exist. This is unnecessary and complicates the resulting data structure when the goal is simply to augment sales with target data.
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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.