Intermediate
SQL
Q45 / 100
What is the difference between UNION and UNION ALL?
Correct! Well done.
Incorrect.
The correct answer is B) UNION removes duplicate rows from the combined result, while UNION ALL keeps all rows including duplicates, making it generally faster
B
Correct Answer
UNION removes duplicate rows from the combined result, while UNION ALL keeps all rows including duplicates, making it generally faster
Explanation
UNION performs an implicit DISTINCT on the combined results (requiring a sort/dedup step), whereas UNION ALL simply concatenates results without removing duplicates.
Progress
45/100