I have two table. Department is hierarchical table.
Department
--- id (int primary key)
--- name (varchar)
--- parent (int)
Users
--- Id
--- name
--- department_id
This query return all data from departments. But i cannot understand how get data from users
SELECT t1.name AS lvl1, t2.name as lvl2, t3.name as lvl3
FROM Department AS t1
LEFT JOIN Department AS t2 ON t2.parent = t1.id
LEFT JOIN Department AS t3 ON t3.parent = t2.id