IS NULL CONDITION

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

DESCRIPTION

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

SYNTAX

The syntax for the SQL IS NULL condition is:

expression IS NULL

Parameters or Arguments

expression

The expression to test for 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 IS NULL in a SELECT statement:

SELECT *
FROM suppliers
WHERE supplier_name IS NULL;

This SQL IS NULL example will return all records from the suppliers table where the supplier_name contains a NULL value.

EXAMPLE - WITH INSERT STATEMENT

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

INSERT INTO suppliers
(supplier_id, supplier_name)
SELECT account_no, name
FROM customers
WHERE city IS NULL;

This SQL IS NULL example will insert records into the suppliers table where the city contains a NULL value.

EXAMPLE - WITH UPDATE STATEMENT

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

UPDATE suppliers
SET supplier_name = 'Apple'
WHERE supplier_name IS NULL;

This SQL IS NULL example will update records in the suppliers table where the supplier_name contains a NULL value.

EXAMPLE - WITH DELETE STATEMENT

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

DELETE FROM suppliers
WHERE supplier_name IS NULL;

This SQL IS NULL example will delete all records from the suppliers table where the supplier_name contains a NULL value