表结构

进行树形结构查询，利用特殊语法进行操作

with recursive t as
         (
                         select parent_id , business_name
                         from business_line  where id = 21
                         union all
                         select a.parent_id, a.business_name
                         from business_line a join t on a.id = t.parent_id
         )
select business_name from t;

查询结果：