# COLUMN\_CHECK

## Syntax

```sql
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](https://mariadb.com/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_create), [COLUMN\_ADD](https://mariadb.com/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_add), [COLUMN\_DELETE](https://mariadb.com/docs/server/reference/sql-functions/special-functions/dynamic-columns-functions/column_delete) 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.

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