> For the complete documentation index, see [llms.txt](https://upsolver.gitbook.io/content/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://upsolver.gitbook.io/content/reference-1/functions-and-operators/functions/string/bytes_substring.md).

# BYTES\_SUBSTRING

Returns a substring of the input value, using the offsets in bytes of the UTF-8 encoded byte representation. Partial characters and invalid UTF-8 code points are removed from the result.

## Syntax

Use the following syntax to include the `BYTES_SUBSTRING` function in your query:

```sql
BYTES_SUBSTRING(value, startIndex, endIndex)
```

## Arguments

The `BYTES_SUBSTRING` function requires the following arguments:

* `value` input is the string upon which you want to perform the substring function. 
* `startIndex` begins at `1` and includes the first character in your string. 
* `endIndex` counts from the first character in the string, not from the `startIndex` position.  

<table><thead><tr><th>Name</th><th width="138.33333333333331">Type</th><th>Description</th><th data-hidden>Default Value</th></tr></thead><tbody><tr><td>value</td><td>string</td><td>The input value to perform the substring function on</td><td></td></tr><tr><td>startIndex</td><td>int</td><td>The inclusive start index in bytes</td><td></td></tr><tr><td>endIndex</td><td>int</td><td>The exclusive end index in bytes</td><td></td></tr></tbody></table>

## Returns

Returns a `string` value.

***

## Examples

The following example shows how the `startIndex` and `endIndex` arguments affect the `Output` value. Here, the `endIndex` value demonstrates that regardless of the `startIndex` value, the `endIndex` works from position **1** in the string to include **10** characters. &#x20;

<table><thead><tr><th>value</th><th width="169">startIndex</th><th width="148">endIndex</th><th>Output</th></tr></thead><tbody><tr><td>'Hello World'</td><td>1</td><td>10</td><td><code>Hello Worl</code></td></tr><tr><td>'Hello World'</td><td>2</td><td>10</td><td><code>ello Worl</code></td></tr><tr><td>'⻤Hello Wor⻤'</td><td>2</td><td>10</td><td><code>Hello W</code></td></tr><tr><td>'⻤Hello Wor⻤'</td><td>1</td><td>10</td><td><code>⻤Hello W</code></td></tr><tr><td>'Hello'</td><td>1</td><td>10</td><td><code>Hello</code></td></tr></tbody></table>

### Transformation job example

The script below includes the `BYTES_SUBSTRING` function in a `SELECT` statement within a transformation job, using the "Hello World" string example.&#x20;

#### SQL

```sql
CREATE JOB function_operator_example
    ADD_MISSING_COLUMNS = true
AS INSERT INTO default_glue_catalog.upsolver_samples.orders_transformed_data 
  MAP_COLUMNS_BY_NAME
    SELECT value, startIndex, endIndex,
        BYTES_SUBSTRING(value, 1, 10) AS Output
    FROM default_glue_catalog.upsolver_samples.orders_raw_data
    LET value = 'Hello World',
        startIndex = 1,
        endIndex = 10      
    WHERE $commit_time BETWEEN run_start_time() AND run_end_time()
    LIMIT 1;
```

#### Query result

<table><thead><tr><th>value</th><th width="146">startIndex</th><th width="142">endIndex</th><th>Output</th></tr></thead><tbody><tr><td>'Hello World'</td><td>1</td><td>10</td><td><code>Hello Worl</code></td></tr></tbody></table>


---

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