MySQL: IS NULL Condition

This MySQL tutorial explains how to use the MySQL IS NULL condition with syntax and examples.

Description

The MySQL IS NULL Condition is used to test for a NULL value in a SELECT, INSERT, UPDATE, or DELETE statement.

Syntax

The syntax for the IS NULL Condition in MySQL is:

expression IS NULL

Parameters or Arguments

expression

The value to test if it is a NULL value.

Note

• If expression is a NULL value, the condition evaluates to TRUE.
• If expression is not a NULL value, the condition evaluates to FALSE.

Example - With SELECT Statement

Let's look at an example of how to use MySQL IS NULL in a SELECT statement:

SELECT *

FROM contacts

WHERE last_name IS NULL;

This MySQL IS NULL example will return all records from the contacts table where the last_name contains a NULL value.

Example - With INSERT Statement

Next, let's look at an example of how to use MySQL IS NULL in an INSERT statement:

INSERT INTO contacts

(contact_id, contact_name)

SELECT account_no, supplier_name

FROM suppliers

WHERE category IS NULL;

This MySQL IS NULL example will insert records into the contacts table where the category contains a NULL value.

Example - With UPDATE Statement

Next, let's look at an example of how to use MySQL IS NULL in an UPDATE statement:

UPDATE contacts

SET last_name = 'TBD'

WHERE last_name IS NULL;

This MySQL IS NULL example will update records in the contacts table where the last_name contains a NULL value.

Example - With DELETE Statement

Next, let's look at an example of how to use MySQL IS NULL in a DELETE statement:

DELETE FROM contacts

WHERE last_name IS NULL;

This MySQL IS NULL example will delete all records from the contacts table where the last_name contains a NULL value.