​The Following SQL Statement Contains Which Type of Subquery

question 34

Multiple Choice

​The following SQL statement contains which type of subquery?
​ SELECT title,retail,category,cataverage FROM books NATURAL JOIN
(SELECT category,AVG(retail) cataverage FROM books GROUP BY category) ;

• A) ​single-row
• B) ​multiple-row
• C) ​correlated
• D) ​uncorrelated

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Definitions:

Antigens

Substances, usually proteins, on the surface of bacteria, viruses, and other foreign substances, that trigger an immune response in the body.

Allergens

Substances that cause allergic reactions by triggering an immune response in susceptible individuals.

Lymphocytes

White blood cells that circulate through the lymph system and bloodstream, helping the body identify and destroy antigens and cancer cells.

Antigens

Substances that the immune system recognizes as foreign or dangerous, leading to an immune response.