IS NULL

Test NULL values with IS NULL and IS NOT NULL.

With IS NULL you check whether a column is empty. = NULL does not work; always use IS NULL for NULL checks.

SELECT name FROM customers
WHERE email IS NULL;

This query customers whose email is empty.

name is selected from customers. WHERE keeps only the rows where email IS NULL holds.

IS NULL — details

NULL means an unknown value; it is not a space or zero. Use IS NOT NULL to filter non-empty rows.

Select names from customers where email is not null.

Show example solution

SELECT name
FROM customers
WHERE email IS NOT NULL

Not null

SELECT name FROM customers
WHERE email ____;

Show answer

SELECT name FROM customers
WHERE email IS NOT NULL;