SQL Keywords: IS

The IS keyword is used in a WHERE statement to specify a condition used to find a record.

Here is an example:

SELECT LastName, FirstName, HourlySalary
FROM   Employees
WHERE  Department IS NULL

You can negate an IS condition by following it with the NOT operator. An example would be to get an IS NOT NULL expression. Here is an example:

SELECT LastName, FirstName, HourlySalary
FROM   Employees
WHERE  Department IS NOT NULL