SQL - Set Operations
What does the
UNION operation do when combining results from two SELECT queries?What does the UNION operation do when combining results from two SELECT queries?
easy📝 Conceptual Q11 of 15
Step-by-Step Solution
Solution:
Step 1: Understand UNION operation
The UNION operation combines results from two SELECT queries into one result set.Step 2: Check duplicate handling
UNION removes duplicate rows, unlike UNION ALL which keeps duplicates.Final Answer:
Combines results and removes duplicate rows -> Option BQuick Check:
UNION removes duplicates = C [OK]
Quick Trick: UNION removes duplicates; UNION ALL keeps them [OK]
Common Mistakes:
MISTAKES- Confusing UNION with UNION ALL
- Thinking UNION sorts results automatically
- Mixing UNION with JOIN operations
Master "Set Operations" in SQL
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