SQL Is Not Null
Example Table
We will use the following table named employees for our examples:
CREATE TABLE employees (
employee_id INT PRIMARY KEY,
employee_name VARCHAR(50),
department VARCHAR(50),
salary DECIMAL(10, 2)
);
INSERT INTO employees (employee_id, employee_name, department, salary) VALUES
(1, 'John Doe', 'HR', 50000.00),
(2, 'Jane Smith', 'Finance', 60000.00),
(3, 'Emily Davis', 'IT', NULL),
(4, 'Michael Brown', NULL, 80000.00),
(5, 'Jessica Wilson', 'IT', 90000.00);
Employees Table
| employee_id | employee_name | department | salary |
|---|---|---|---|
| 1 | John Doe | HR | 50000.00 |
| 2 | Jane Smith | Finance | 60000.00 |
| 3 | Emily Davis | IT | NULL |
| 4 | Michael Brown | NULL | 80000.00 |
| 5 | Jessica Wilson | IT | 90000.00 |
Using SQL IS NOT NULL
The SQL IS NOT NULL operator is used to test for non-empty values (i.e., values that are not NULL) in a column.
Example 1: Select Employees with Non-NULL Salaries
To select employees who have a salary that is not NULL, use the following query:
SELECT employee_name, salary
FROM employees
WHERE salary IS NOT NULL;
Result:
| employee_name | John Doe |
|---|---|
| salary | 50000.00 |
| Jane Smith | |
| 60000.00 | |
| Michael Brown | |
| 80000.00 | |
| Jessica Wilson | |
| 90000.00 |
Example 2: Select Employees with Non-NULL Departments
To select employees who have a department that is not NULL, use the following query:
SELECT employee_name, department
FROM employees
WHERE department IS NOT NULL;
Result:
| employee_name | John Doe |
|---|---|
| department | HR |
| Jane Smith | |
| Finance | |
| Emily Davis | |
| IT | |
| Jessica Wilson | |
| IT |