661. Lowercase emails — function task 1

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

Write the MySQL query using appropriate string/date/NULL functions.

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Answer & Explanation

4 Answers

Verified Correct Answer

Option A

SELECT id,LOWER(TRIM(email)) AS normalized_email FROM customers WHERE email IS NOT NULL;

Additional Explanation

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

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Option B

Compare NULL using = NULL.

Additional Explanation

This option is incorrect for the stated requirement.

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Option C

Use DELETE for the transformation.

Additional Explanation

This option is incorrect for the stated requirement.

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Option D

Use string concatenation without handling NULL values.

Additional Explanation

This option is incorrect for the stated requirement.