What Is NULL Value in MySQL

Q

What Are NULL Values in MySQL?

✍: FYIcenter.com

A

NULL is a special value that represents no value. Here are basic rules about NULL values:

  • NULL presents no value.
  • NULL is not the same as an empty string ''.
  • NULL is not the same as a zero value 0.
  • NULL can be used as any data type.
  • NULL should not be used in any comparison options.
  • NULL has its own equality operator "IS".
  • NULL has its own not-equality operator "IS NOT".

The tutorial exercise shows you some interesting examples:

SELECT 0 IS NULL FROM DUAL;
   0

SELECT 0 IS NOT NULL FROM DUAL;
   1

SELECT '' IS NULL FROM DUAL;
   0

SELECT '' IS NOT NULL FROM DUAL;
   1

SELECT NULL IS NULL FROM DUAL;
   1

SELECT NULL IS NOT NULL FROM DUAL;
   0

 

Introduction to SQL Basics in MySQL

⇒⇒MySQL Database Tutorials

2016-10-16, 202👍, 0💬