Oracle Database MySQL 5.6 Developer — Question 19

Which two queries return a value of NULL?

Answer options

• A. SELECT NULL =NULL
• B. SELECT NULL is NULL
• C. SELECT NULL <= > NULL
• D. SELECT 1 > NULL
• E. SELECT COUNT (NULL);

Correct answer: A, D

Explanation

The query SELECT NULL = NULL (A) returns NULL because NULL is not considered equal to NULL in SQL. Similarly, SELECT 1 > NULL (D) also returns NULL since any comparison with NULL results in an unknown value. The other options either explicitly return TRUE or FALSE, or count NULL values, which does not yield NULL.