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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