# Advanced Search

Snowray provides an advanced search option for Custom Code Systems, which can be invoked by pressing the![](https://241429605-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FVwwvGKUkhNz5JGk0Ltmd%2Fuploads%2FUqvakAUIcvtEdwNCmm9I%2Fadvanced_search_icon.png?alt=media)advanced filter icon in the search bar. This enables users to specify additional criteria to restrict their searches.

![Advanced Filter Search](https://241429605-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FVwwvGKUkhNz5JGk0Ltmd%2Fuploads%2FhmZhE93O3X1xSUn5hxO2%2Fcode_system_advanced_filter_search.png?alt=media\&token=fc10cb53-6380-4802-92ff-60eaa750f15b)

The `Status` filter is a dropdown, while the ECL filter requires typing in a valid query using an improved version of [SNOMED CT Expression Constraint Language](https://snomed.org/ecl) that allows any kind of identifier to be used, not just SCT IDs. A content assist, which can be activated by pressing `Ctrl` + `Space`, helps users to construct ECL queries easily.

{% hint style="info" %}
The ECL evaluation of non-SNOMED CT terminologies supports the following basic operators: `=`, `<`, `<<`, `<!`, `^`, `*`, `AND`, `OR`, `MINUS`
{% endhint %}
