Multiple choice technology databases

UNION query returns only distinct rows and UNION ALL may return duplicates.

  1. True

  2. False
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A Correct answer
Explanation

UNION eliminates duplicate rows from the combined result set, effectively performing a DISTINCT operation. UNION ALL preserves all rows including duplicates, which makes it faster and useful when you know there are no duplicates or want to keep them. The statement correctly describes this key difference.

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