Syntax
------

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, COLUMN_ADD, 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.

URL: https://mariadb.com/kb/en/column_check/