Oracle Database SQL — Question 154

Which three are true about subqueries? (Choose three.)

Answer options

• A. A subquery cannot be used in the select list.
• B. < ANY returns true if the argument is less than the highest value returned by the subquery.
• C. < ANY returns true if the argument is less than the lowest value returned by the subquery.
• D. A subquery can be used in a HAVING clause.
• E. A subquery cannot be used in a FROM clause.
• F. A subquery can be used in a WHERE clause.
• G. = ANY can only evaluate the argument against a subquery if it returns two or more values.

Correct answer: B, D, F

Explanation

The correct answers are B, D, and F. Option B is true because < ANY evaluates to true when the argument is less than the highest subquery result. Option D is correct as subqueries can indeed be employed in HAVING clauses. Option F is valid since subqueries are commonly used in WHERE clauses. Options A and E are incorrect because subqueries can be used in the select list and FROM clause, respectively. Option C misinterprets the functionality of < ANY, and G is misleading as = ANY can evaluate against a single value.