400. Departments with no employees — join challenge 3

DBMS Published 30 Sept 2026 Updated 30 Sept 2026 0 Views Verified

Write the MySQL query for the following relational reporting requirement. Pay attention to unmatched rows and duplicate multiplication.

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Answer & Explanation

4 Answers

Verified Correct Answer

Option A

SELECT d.id, d.name FROM departments d LEFT JOIN employees e ON e.dept_id=d.id WHERE e.id IS NULL;

Additional Explanation

Correct implementation. Prefer parameterized queries in application code, validate affected rows for UPDATE/DELETE, and use transactions for related writes.

Verified

Option B

Use CROSS JOIN for the relationship.

Additional Explanation

This option is incorrect for the stated requirement.

Verified

Option C

Use INNER JOIN even when unmatched left rows must remain.

Additional Explanation

This option is incorrect for the stated requirement.

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Option D

Join on unrelated text columns instead of the key.

Additional Explanation

This option is incorrect for the stated requirement.