mysql查询树形接口的所有子节点，查询表： shi_point_chapter ，的3层子节点

SELECT id,title,title2,isLeaf,parentId,treeDeep,showorder from shi_point_chapter c         where parentId=420435 or parentId in         (SELECT id from shi_point_chapter where parentId=420435 )         or parentId in         (SELECT id from shi_point_chapter  where parentId in (SELECT id from shi_point_chapter where parentId=420435))         or parentId in         (SELECT id from shi_point_chapter where parentId in         (SELECT id from shi_point_chapter  where parentId in (SELECT id from shi_point_chapter where parentId=420435)))