> For the complete documentation index, see [llms.txt](https://docs.b2ihealthcare.com/snowray/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.b2ihealthcare.com/snowray/v2.9/reference/resources/codesystems/custom-code-systems/advanced-search.md).

# Advanced Search

Snowray provides an advanced search option for Custom Code Systems, which can be invoked by pressing the <img src="https://848337088-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FNfVt73uJmV35VTVsq2mk%2Fuploads%2FmQFFerOjoQnRAL3W3clV%2Ffilter_icon.svg?alt=media&amp;token=36020cf7-438f-45a1-a7ca-3b6fdc6662cd" alt="" data-size="line"> advanced filter icon in the search bar. This enables users to specify additional criteria to restrict their searches.

![Advanced Filter Search](https://848337088-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FNfVt73uJmV35VTVsq2mk%2Fuploads%2FnTvs8Wa6i4xOhtO3VWSH%2Fcode_system_advanced_filter_search.png?alt=media\&token=ea02f1a4-2026-49e9-be2d-abfc893d21db)

The `Status` can be filtered using the radio buttons, 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 %}

Once the required filters are specified, pressing ![](https://848337088-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FNfVt73uJmV35VTVsq2mk%2Fuploads%2FhUvvPD2QX6pTDHmsw9NZ%2Fapply_filter_button.png?alt=media\&token=6fb2ec49-7a95-469d-bc14-26447837bf5c)will update the tree only with the matching results as per the filters.&#x20;