Oracle Database SQL — Question 81

Which statement is true about aggregate functions?

Answer options

• A. Aggregate functions can be nested to any number of levels.
• B. The AVG function implicitly converts NULLS to zero.
• C. The MAX and MIN functions can be used on columns with character data types.
• D. Aggregate functions can be used in any clause of a SELECT statement.

Correct answer: C

Explanation

Option C is correct because both the MAX and MIN functions can operate on character data types, returning the highest and lowest values respectively. Option A is incorrect as there may be practical limits to nesting. Option B is wrong since the AVG function does not treat NULLS as zero but rather ignores them in calculations. Option D is incorrect because aggregate functions are typically used in the SELECT clause or HAVING clause rather than every clause.