IS_UUID(string_uuid)

Returns 1 if the argument is a valid string-format UUID, 0 if the
argument is not a valid UUID, and NULL if the argument is NULL.

"Valid" means that the value is in a format that can be parsed. That
is, it has the correct length and contains only the permitted
characters (hexadecimal digits in any lettercase and, optionally,
dashes and curly braces). This format is most common:

aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee

These other formats are also permitted:

aaaaaaaabbbbccccddddeeeeeeeeeeee
{aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee}

For the meanings of fields within the value, see the UUID() function
description.

URL: https://dev.mysql.com/doc/refman/8.0/en/miscellaneous-functions.html

