PostgreSQL – IS NULL Operator
The IS NULL operator is used to check if a value is NULL. It’s used in SQL queries to filter rows where a specific column has a NULL value.
The syntax for using the IS NULL operator is as follows:
SELECT columns FROM table_name WHERE column_name IS NULL;Here’s an example of using the IS NULL operator:
SELECT product_name FROM products WHERE expiration_date IS NULL;In this example, the query retrieves the product names for products where the expiration date is NULL.
You can also use the IS NOT NULL operator to check for non-null values:
SELECT employee_name FROM employees WHERE email IS NOT NULL;In this example, the query retrieves the names of employees who have an email address that is not NULL.
The IS NULL and IS NOT NULL operators are crucial when dealing with nullable columns in your database. They allow you to filter rows based on the presence or absence of values, helping you manage and retrieve data accurately.