# **IS NOT**

## **Grammar Description**

The `IS NOT` operator is used to test whether the value is a Boolean value. If it is not a Boolean value, the result is `true`. where `boolean_value` can be `TRUE`, `FALSE` or `UNKNOWN`.

## **Grammar Structure**

```text
> IS NOT boolean_value
```

## **Example**

```text
mysql> SELECT 1 IS NOT TRUE, 0 IS NOT FALSE, NULL IS NOT UNKNOWN;
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| 1 is not true | 0 is not false | null is not unknown |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| false | false | false |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 row in set (0.01 sec)
```