Why must the ORDER BY clause appear only once after all set operations like UNION or INTERSECT in a SQL query?

hard📝 Conceptual Q10 of 15

SQL - Set Operations

ABecause ORDER BY is not allowed in any SELECT statement

BBecause ORDER BY sorts the final combined result set, not individual queries

CBecause ORDER BY can only sort numeric columns

DBecause ORDER BY must be inside each SELECT before UNION

Step-by-Step Solution

Solution:

Step 1: Understand set operation behavior
Set operations combine multiple query results into one final set.
Step 2: Role of ORDER BY
ORDER BY sorts the entire combined result, so it must appear once at the end.
Final Answer:
ORDER BY sorts the final combined result set, not individual queries -> Option B
Quick Check:
ORDER BY after set operations sorts combined output [OK]

Quick Trick: ORDER BY sorts combined results; place it once at the end [OK]

Common Mistakes:

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