Teach Cloud - Cloud, DevOps, and Python Backend Development Blog

❓ Quiz Question

Aug 30, 2026

Quiz: What is the outcome of a SQL ROLLBACK statement during a transaction?

ROLLBACK reverts database modifications made since the last BEGIN TRANSACTION point.

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❓ Quiz Question

Aug 30, 2026

UNION performs a distinct deduplication pass on combined records; UNION ALL appends records directly, providing faster performance.

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❓ Quiz Question

Aug 30, 2026

COALESCE(val1, val2, fallback) evaluates arguments sequentially and returns the first non-null value encountered.

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❓ Quiz Question

Aug 30, 2026

Deadlocks occur when concurrent transactions acquire circular locks; database engines detect deadlocks and abort one of the transactions.

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❓ Quiz Question

Aug 30, 2026

If two rows tie for rank 1, RANK() assigns the next row rank 3, whereas DENSE_RANK() assigns rank 2.

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❓ Quiz Question

Aug 30, 2026

WHERE operates on individual rows before grouping; HAVING operates on aggregated summary rows.

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❓ Quiz Question

Aug 30, 2026

CASE WHEN condition THEN val ELSE fallback END enables inline conditional projection within query results.

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❓ Quiz Question

Aug 30, 2026

Correlated subqueries reference parent query columns, re-evaluating for every outer row processed.

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