---
title: querystring.filter_except
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/functions/query-string/querystring-filter-except
---

```
STRING querystring.filter_except(STRING url, STRING names)
```

**Available in:** all subroutines

Returns the given URL but only keeps the listed parameters.

## Example

```vcl
set req.url = querystring.filter_except(req.url, "q" + querystring.filtersep() + "p");
```