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CompTIA Data+ DA0-002 · Domain 2: Data acquisition and preparation

Combining data: inner, left, right and full joins, unions and appending

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Last reviewed September 25, 2026 · Leer en español

Real analysis almost always needs data from more than one table or file. You combine data sideways with joins, adding columns by matching keys, or stack it vertically with unions, adding rows. Choosing the wrong one is a leading cause of missing or inflated numbers.

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