Excluding Rows with NOT: SQL lesson

Sometimes it's easier to say what you don't want.

Use != for "not equal" (<> means the same thing):

SELECT first_name, department_id
FROM employees
WHERE department_id != 1;

NOT flips any condition you already know:

SELECT first_name FROM employees
WHERE department_id NOT IN (1, 2);

SELECT first_name FROM employees
WHERE first_name NOT LIKE 'J%';

SELECT first_name, salary FROM employees
WHERE salary NOT BETWEEN 100000 AND 150000;

You've already seen one of these: IS NOT NULL.

Watch out: != never matches NULL. Alice and Robert have no manager, so this quietly leaves them out:

SELECT first_name FROM employees
WHERE manager_id != 1;

To keep them, check for NULL as well:

SELECT first_name FROM employees
WHERE manager_id != 1
   OR manager_id IS NULL;

Examples run on the employees sample database. Open any of them in the playground to experiment.