# Containing neither

Learn how to check if a collection has no intersection with another.

This operator checks whether one collection does not contain any of the elements of another. It is the opposite of the [`containing either`](/reference/cql/expressions/events/criteria/operators/containing-either) test.

Note that the result is always true if the second collection is empty because the [empty set is disjoint from every set](https://en.wikipedia.org/wiki/Empty_set#properties). This is different from the [`containing none`](/reference/cql/expressions/events/criteria/operators/containing-none) test, which returns false in this case, as it operates on the idea of subset rather than intersection.

Also, keep in mind that neither the order nor duplicate elements affect the result since collections are treated as [sets](/reference/cql/data-types/core/collection#set).

> **Multi-condition criteria**
>
> You can [combine conditions](/reference/cql/expressions/events/criteria/overview#multi-condition-criteria) to create more advanced criteria.

## Syntax

The basic syntax is:

```cql
with /*<property>*/ containing neither /*<collection>*/
```

Alternatively, you can use the `including` keyword:

```cql
with /*<property>*/ including neither /*<collection>*/
```

The negation of this operation can be expressed as:

```cql
with /*<property>*/ not containing neither /*<collection>*/
```

Using the alternative syntax:

```cql
with /*<property>*/ not including neither /*<collection>*/
```

## Parameters

These are the supported parameters:

- `name`: `collection`

  The name of the [event property](/reference/cql/expressions/events/event-types) to search for in the collection.

- `collection`: `collection`

  The collection to check.

## Examples

Check if a post with none of the specified tags was viewed:

```cql
user has viewed post with tags containing neither ["news", "cases"]
```

Or to check the opposite:

```cql
user has viewed post with tags not containing neither ["news", "cases"]
```