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

❓ Quiz Question

Aug 30, 2026

Quiz: What is the purpose of the SQL EXPLAIN command?

EXPLAIN (or EXPLAIN ANALYZE ) shows how database engines execute queries, highlighting index usage and scan costs.

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❓ Quiz Question

Aug 30, 2026

In SQL LIKE queries, % matches arbitrary length substrings, while _ matches a single character.

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❓ Quiz Question

Aug 30, 2026

INNER JOIN excludes unmatched records; LEFT JOIN retains all records from the left table, populating NULLs for unmatched right table columns.

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❓ Quiz Question

Aug 30, 2026

Atomicity guarantees that all operations within a database transaction execute successfully, or the entire transaction is rolled back completely.

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❓ Quiz Question

Aug 30, 2026

ROW_NUMBER() generates a strictly incremental sequence number for each row inside a window partition.

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❓ Quiz Question

Aug 30, 2026

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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