MySql获取树型结构的所有子节点

stackoverflow的解决方案,亲测有效:

SELECT * FROM person WHERE department IN
(SELECT department_id FROM department WHERE department_id =
UNION
(SELECT department_id FROM
  (SELECT  * FROM department ORDER BY parent_id,department_id) depart_sorted,
  (SELECT @pv := ) initialisation
WHERE find_in_set(parent_id,@pv)
AND length(@pv := concat(@pv,',',department_id))));

sql:

CREATE TABLE department
(
    id BIGINT() PRIMARY KEY NOT NULL AUTO_INCREMENT,
    department_id INT() NOT NULL,
    parent_id INT(),
    department_level INT() NOT NULL,
    department_name VARCHAR(),
    attend_group VARCHAR()
);