> For the complete documentation index, see [llms.txt](https://docs.wem.io/platform/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wem.io/platform/wemreference/functions/text/substring.md).

# SubString

{% hint style="info" %}
The **`Substring()`** function returns a subset of a <mark style="color:blue;">text</mark>.&#x20;

This function is NOT SQL compatible. For more information about SQL compatibility, see our [documentation](/platform/wemreference/sql-compatibility.md).

WEM functions are 1-based where it concerns position parameters: 1 is the first position.
{% endhint %}

{% hint style="success" %}
Returns a new <mark style="color:green;">text</mark> that is a subset of <mark style="color:blue;">`text`</mark> beginning at a position through a number of characters. \
Returns <mark style="color:red;">`Invalid expression`</mark> if one of the parameters is not valid.&#x20;

If length-parameter is longer than the length of text, the result will be from the indicated start\_position until the last character.
{% endhint %}

### Syntax

<details>

<summary><code>Substring(</code><mark style="color:blue;"><code>text</code></mark><code>,</code><mark style="color:blue;"><code>length</code></mark><code>)</code></summary>

*If only the length parameter is provided, the result will be taken from the first character of the text-value.*&#x20;

`Substring("Important", 6)`\
\=> *"Import"* &#x20;

`Substring("Important", 16)`\
\=> *"Important"* &#x20;

</details>

<details>

<summary><code>Substring(</code><mark style="color:blue;"><code>text</code></mark><code>,</code><mark style="color:blue;"><code>start_position</code></mark><code>,</code><mark style="color:blue;"><code>length</code></mark><code>)</code></summary>

*If start\_position is specifically provided, the result will be taken from the indicated starting position with the understanding that position 1 is the first character.* \
*If 0 (zero) is used as start\_position, it will also use the first character to start from.*&#x20;

`Substring("Important", 3, 4)`\
\=> *"port"*

`Substring("Important", 1, 2)`\
\=> *"Im"*

`Substring("Important", 0, 2)`\
\=> *"Im"*

`Substring("Important", 4, 16)`\
\=> *"ortant"*

</details>

### Parameters

<table><thead><tr><th width="202.70825474075613">Name</th><th width="150">Type</th><th width="150" align="center">Required</th><th width="248.15953250810662">Description</th><th data-hidden>Required?</th></tr></thead><tbody><tr><td><mark style="color:blue;"><code>text</code></mark></td><td>text</td><td align="center"><span data-gb-custom-inline data-tag="emoji" data-code="2611">☑️</span></td><td>a text</td><td>yes</td></tr><tr><td><mark style="color:blue;"><code>start_position</code></mark></td><td>numeric</td><td align="center"></td><td>(<em>optional</em>) the position to start from. 1-based, so the first character is start_position 1.</td><td></td></tr><tr><td><mark style="color:blue;"><code>length</code></mark></td><td>numeric</td><td align="center"><span data-gb-custom-inline data-tag="emoji" data-code="2611">☑️</span></td><td>the number of characters to take from <code>text</code></td><td></td></tr></tbody></table>


---

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