SELECT d.`iD`, d.`subsectionOf`,
CONCAT(REPEAT('-', p.`len`), d.`name`) as hier,
p.`len`, p.`ancestor`, p.`descendant`,
GROUP_CONCAT(crumbs.`ancestor`) AS breadcrumbs
FROM `TreeData` AS d
JOIN `TreePaths` AS p ON d.`iD` = p.`descendant`
JOIN `TreePaths` AS crumbs ON crumbs.`descendant` = p.`descendant`
WHERE p.`ancestor` = 1
GROUP BY d.`iD`
ORDER BY breadcrumbs;
+----+--------------+---------------------+-----+----------+------------+-------------+
| iD | subsectionOf | hier | len | ancestor | descendant | breadcrumbs |
+----+--------------+---------------------+-----+----------+------------+-------------+
| 1 | NULL | Root A | 0 | 1 | 1 | 1 |
| 2 | 1 | -Item 1 | 1 | 1 | 2 | 1,2 |
| 5 | 2 | --Item 1 Sub Item 2 | 2 | 1 | 5 | 1,2,5 |
| 6 | 2 | --Item 1 Sub Item 1 | 2 | 1 | 6 | 1,2,6 |
| 3 | 1 | -Item 2 | 1 | 1 | 3 | 1,3 |
| 4 | 1 | -Item 3 | 1 | 1 | 4 | 1,4 |
| 8 | 4 | --Item 3 Sub Item 1 | 2 | 1 | 8 | 1,4,8 |
| 9 | 4 | --Item 3 Sub Item 2 | 2 | 1 | 9 | 1,4,9 |
| 7 | 1 | -Item 4 | 1 | 1 | 7 | 1,7 |
+----+--------------+---------------------+-----+----------+------------+-------------+
