UNION vs. UNION ALL

  1. UNION only selects distinct values, UNION ALL selects all values (excluding ?duplicates)?

  2. UNION ALL only selects distinct values, UNION selects all values (including ?duplicates)?

  3. UNION only selects distinct values, UNION ALL selects all values (including ?duplicates)?

  4. UNION ALL only selects distinct values, UNION selects all values (excluding ?duplicates)?


Correct Option: C

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