# Query Filters

Query Filters let you interactively reduce the amount of data shown in your visualizations, similar to Query Parameters but with a few key differences. Query Filters limit data **after** it has been loaded into your browser. This makes them ideal for smaller datasets and environments where query executions are time-consuming, rate-limited, or costly.

### 1. Usage

Unlike Query Parameters there isn’t a button to add a filter. Instead, if you want to focus on a specific value, just alias your column to `<columnName>::filter`. Here’s an example:

```sql
SELECT action AS "action::filter", COUNT(0) AS "actions count"
FROM events
GROUP BY action
```

{% hint style="info" %}
Note that you can use<mark style="background-color:blue;">`__filter`</mark> or <mark style="background-color:blue;">`__multiFilter`</mark>, (double underscore instead of double quotes) if your database doesn’t support :: in column names (such as BigQuery).
{% endhint %}

![](https://redash.io/assets/images/docs/gitbook/filter_example_action_create.png)

If you need a multi-select filter then alias your column to `<columnName>::multi-filter`.

```
SELECT action AS "action::multi-filter", COUNT (0) AS "actions count"
FROM events
GROUP BY action
```

![](https://redash.io/assets/images/docs/gitbook/multifilter_example.png)

You can use Query Filters on dashboards too. By default, the filter widget will appear beside each visualization where the filter has been added to the query. If you’d like to link together the filter widgets into a dashboard-level Query Filter see [these instructions](https://redash.io/help/user-guide/dashboards/dashboard-editing).

### 2. Limitations

Query Filters aren’t suitable for especially large data sets or query results with hundreds or thousands of distinct field values. Depending on your computer and browser configuration, excessive data can deteriorate the user experience.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.inverse.watch/user-guide/queries/query-filters.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.