SQL Basics | DML: Data Manipulation Language | IS NULL, IS NOT NULL

These conditions check whether a field value is empty, that is, whether it is NULL.

IS NULL, IS NOT NULL syntax

The IS NULL condition is as follows.

SELECT "field_name"
FROM "table_name"
WHERE "field_name" IS NULL

To query the opposite of the IS NULL condition, use the following.

SELECT "field_name"
FROM "table_name"
WHERE "field_name" IS NOT NULL

IS NULL example

Given the store_information table below, suppose sales is empty.

store_information table

Enter the following command.

SELECT *
FROM store_information
WHERE sales IS NULL

The result is as follows.

IS NOT NULL example

When sales is not empty, use the following.

SELECT *
FROM store_information
WHERE sales IS NOT NULL

The result is as follows.