Beginner
Database Management Systems
Q18 / 100
What is a NULL value in SQL?
Correct! Well done.
Incorrect.
The correct answer is B) The absence of a value — different from empty string or zero
B
Correct Answer
The absence of a value — different from empty string or zero
Explanation
NULL represents missing or unknown data. NULL arithmetic returns NULL. Use IS NULL / IS NOT NULL (not = NULL). Three-valued logic: TRUE, FALSE, UNKNOWN (NULL comparisons return UNKNOWN).
Progress
18/100