# WEM Expressions Reference

{% hint style="info" %}
**Unknown?**\
In general, a function, keyword or operator returns an `unknown` value if one or more parameters are unknown. Make sure to check for unknown situations using the appropriate functions (HasValue, IsEmpty, IsUnknown and the question mark)
{% endhint %}

{% hint style="info" %}
Most Text-related functions, keywords and operators are case-insensitive and ignore diacritics. You can find the Priority of operations [here.](https://docs.wem.io/platform/wemtipsandtricks/expressions/order-of-operators)
{% endhint %}

{% content-ref url="functions" %}
[functions](https://docs.wem.io/platform/wemreference/functions)
{% endcontent-ref %}

{% content-ref url="keywords" %}
[keywords](https://docs.wem.io/platform/wemreference/keywords)
{% endcontent-ref %}

{% content-ref url="operators" %}
[operators](https://docs.wem.io/platform/wemreference/operators)
{% endcontent-ref %}

{% content-ref url="data-types" %}
[data-types](https://docs.wem.io/platform/wemreference/data-types)
{% endcontent-ref %}

{% content-ref url="sql-compatibility" %}
[sql-compatibility](https://docs.wem.io/platform/wemreference/sql-compatibility)
{% endcontent-ref %}

{% content-ref url="wem-widgets" %}
[wem-widgets](https://docs.wem.io/platform/wemreference/wem-widgets)
{% endcontent-ref %}


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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.wem.io/platform/wemreference/wem-expressions-reference.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.