Question

What does comparing a known value with NULL result into?

(a) zero

(b) a positive value

(c) a negative value

(d) null

I got this question by my school principal while I was bunking the class.

This key question is from MySQL Setup in chapter General MySQL Use of MySQL

Answer 1

Correct answer is (d) null

For explanation: In MySQL, NULL is not comparable to other known values. It will result in a NULL when compared to any value. The following statement would result in four NULLs: ‘SELECT NULL = 0, NULL < 0, NULL <> 0, NULL > 0’.