Oracle Database SQL — Question 101

Which two are true about scalar subquery expressions?

Answer options

• A. They can return at most one row.
• B. You must enclose them in parentheses.
• C. You cannot correlate them with a table in the parent statement.
• D. They can return two columns.
• E. You can use them as a default value for a column.

Correct answer: A, B

Explanation

The correct answers are A and B. Scalar subqueries are designed to return a single value, thus they can only return at most one row (A), and they require enclosing in parentheses (B). Options C, D, and E are incorrect because scalar subqueries can indeed be correlated with tables, cannot return multiple columns, and cannot be used as default values for columns.