1538. Find missing payments — Library — implementation variant 38

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

In a Library application, implement this production problem: Find completed orders that have no successful payment. The API/service receives user input and must return or modify data safely. Give the SQL solution, explain why it works, and show how the same operation is called from the selected stack.

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Answer & Explanation

4 Answers

Verified

Option A

SELECT * FROM the_table;

Additional Explanation

Incorrect: it does not implement the stated business rule and may modify/fetch the wrong rows.

Verified Correct Answer

Option B

SELECT o.id,o.customer_id,o.total_amount FROM orders o WHERE o.status='completed' AND NOT EXISTS (SELECT 1 FROM payments p WHERE p.order_id=o.id AND p.status='success');

Additional Explanation

NOT EXISTS expresses the rule directly and avoids NULL-related NOT IN pitfalls.

Verified

Option C

DELETE FROM the_table;

Additional Explanation

Incorrect: it does not implement the stated business rule and may modify/fetch the wrong rows.

Verified

Option D

UPDATE the_table SET status='active';

Additional Explanation

Incorrect: it does not implement the stated business rule and may modify/fetch the wrong rows.