When should you use a relationship instead of a join for two data sets?

Question

Exhibit

Options

• ATo use both data sets across multiple sheets in a visualization.
• BThe data sets are in two separate tables within a single spreadsheet.
• CThe data sets include similar data aggregated at different levels of detail.
• DThe data sets include similar data aggregated up to the highest level.

• A
  8% (2)
• B
  17% (4)
• C
  67% (16)
• D
  8% (2)

Explanation

Option C is correct because relationships are specifically designed to handle tables with mismatched levels of detail (LOD). When one table has sales by day and another has quotas by month, a join would inflate row counts (fan-out), producing incorrect aggregations - a relationship lets the query engine resolve each table at its own granularity and combine results correctly.

Why the distractors fail:

• A is wrong - using data across multiple sheets is simply a feature of any published or multi-table data source, not a reason to choose relationships over joins.
• B is wrong - two tables inside a single spreadsheet is a classic join scenario (same source, same LOD); relationships are more relevant across separate tables or sources.
• D is wrong - if both tables are already at the same (highest) aggregation level, a join works fine because there's no LOD mismatch to protect against.

Memory tip: Think "Relationship = Respects different LODs." Whenever you see "different levels of detail" in an answer choice, that's the relationship keyword - joins assume equal granularity, relationships don't.

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