# How to allow empty param values in data explorer?

**URL:** https://meta.discourse.org/t/how-to-allow-empty-param-values-in-data-explorer/140782
**Category:** Data & reporting
**Tags:** sql-query
**Created:** [February 5, 2020, 8:59pm UTC](https://meta.discourse.org/t/how-to-allow-empty-param-values-in-data-explorer/140782 "2020-02-05T20:59:40Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![Nacho\_Caballero](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/nacho_caballero/32/130189_2.png) [@Nacho\_Caballero](https://meta.discourse.org/u/Nacho_Caballero)
#### Post date: [February 5, 2020, 8:59pm UTC](https://meta.discourse.org/t/how-to-allow-empty-param-values-in-data-explorer/140782/1 "2020-02-05T20:59:40Z")

</div>

I would like to allow a filtering step to be optional, but if I leave the `query` field empty, I get an error:

```plaintext
---[params]
--- string :query = '%'
select uh.details 
from user_histories uh
where uh.details like case 
      when :query is not null then '%' || :query || '%'
      else '%'
      end
limit 5

```

Error: DataExplorer::ValidationError: Missing parameter query of type string