SQL is null vs = null

By Pradyumna Chippigiri

January 24, 2026

I felt like I was too late to learn this, but learnt it nevertheless.

In SQL, NULL means a missing unknown value right, so it cannot work with arithmetic comparison operators such as =, <, or <>

For example when you do :

SELECT * FROM users WHERE email = NULL;

This returns zero rows because the result of any arithmetic comparison with NULL is also NULL

Whereas,

SELECT * FROM users WHERE email IS NULL;

Use IS NULL (or IS NOT NULL) to check for missing values.