# Not

This function can be used to reverse the truthiness of a value.

This function can be used to reverse the truthiness of a value.

<table>
  <thead>
    <tr>
      <th scope="col">Function</th>
      <th scope="col">Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td scope="row" data-label="Function"><a href="#not"><code>not()</code></a></td>
      <td scope="row" data-label="Description">Reverses the truthiness of a value.</td>
    </tr>
  </tbody>
</table>

## `not`

The `not` function reverses the truthiness of a value. It is functionally identical to `!`, the [NOT](/docs/reference/query-language/language-primitives/operators.md#not) operator.

```surql title="API DEFINITION"
not(any) -> bool
```

```surql
RETURN not("I speak the truth");
-- false
```

A value is not [truthy](/docs/reference/query-language/language-primitives/data-types/values.md#values-and-truthiness) if it is NONE, NULL, false, empty, or has a value of 0. As such, all the following return `true`.

```surql
RETURN [
    not(""),
    not(false),
    not([]),
    not({}),
    not(0)
];
```

Similarly, the function can be used twice to determine whether a value is truthy or not. As each item in the example below is truthy, calling `not()` twice will return the value `true` for each.

```surql
RETURN [
    not(not("I have value")),
    not(not(true)),
    not(not(["value!"])),
    not(not({i_have: "value"})),
    not(not(100))
];
```

Doubling the `!` operator is functionally identical to the above and is a more commonly seen pattern.

```surql
RETURN [
    !!"I have value",
    !!true,
    !!["value!"],
    !!{i_have: "value"},
    !!100
];
```

<br /><br />