> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_check.md).

# COLUMN\_CHECK

## Syntax

```bnf
COLUMN_CHECK(dyncol_blob);
```

## Description

Check if `dyncol_blob` is a valid packed dynamic columns blob. Return value of 1 means the blob is valid, return value of 0 means it is not.

**Rationale:**\
Normally, one works with valid dynamic column blobs. Functions like [COLUMN\_CREATE](/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_create.md), [COLUMN\_ADD](/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_add.md), [COLUMN\_DELETE](/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_delete.md) always return valid dynamic column blobs. However, if a dynamic column blob is accidentally truncated, or transcoded from one character set to another, it will be corrupted. This function can be used to check if a value in a blob field is a valid dynamic column blob.

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

{% @marketo/form formId="4316" %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## 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://mariadb.com/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_check.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.