Alteryx-Core Data Manipulation Practice Question
When joining two datasets, which join type would you use to keep all records from the left input, even if there is no match in the right input?
⚠ Common exam trap
Test takers often select an Inner Join instead of a Left Outer Join when they need to preserve all records from their primary dataset regardless of matches.
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 Outer Join
The Left Outer Join is a fundamental concept in data manipulation. It ensures that the primary dataset remains intact, while matching data from the secondary dataset is appended. Understanding join types is essential for maintaining data completeness. If a developer uses an Inner Join when a Left Join is needed, they will inadvertently lose records, leading to incorrect analysis and incomplete reports that fail to reflect the true state of the source data.
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 only returns records that have matching keys in both the left and right inputs. Any records that do not have a match in the secondary dataset are dropped, violating the requirement to keep all records from the left input.
- ✓
Left Outer Join
Why this is correct
A Left Outer Join preserves all records from the left input stream. If a match is found in the right input, the data is joined; if no match is found, the right-side fields will simply appear as nulls in the output.
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Right Outer Join
Why it's wrong here
A Right Outer Join keeps all records from the right input stream and matches them with the left. This is the opposite of the requested behavior and would result in losing records from the left input if they lack a match.
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Full Outer Join
Why it's wrong here
A Full Outer Join keeps all records from both datasets, regardless of whether a match exists. While this keeps the left records, it also keeps the right records that don't match, which is not what was requested for this specific scenario.
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 Alteryx exam blueprint
This Alteryx-Core practice question is part of Courseiva's free Alteryx 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 Alteryx-Core exam.