Get breadcrumbs for nested set

breadcrumbs.sql

SELECT
    GROUP_CONCAT(
        ancestor.name
        ORDER BY ancestor.lft ASC
        SEPARATOR ' > '
    ),
    child.*
FROM `categories` child
JOIN `categories` ancestor
ON child.lft >= ancestor.lft
AND child.lft <= ancestor.rgt
GROUP BY child.lft
ORDER BY child.lft

I learn new things from this SQL, thanks.