用SQL实现递归

单表：

select t.typeId,t.typeName,t.parentId from t_data t
start with t.typeId = 3
connect by prior t.typeId = t.parentid

关联表：t_ues_pic_rescategory目录表，t_ues_resource 资源表 关联列categoryId

该语句实现递归查询某个目录（包括子目录）下所有资源

select r.*, tp.categoryname
  from t_ues_resource r,
       (select t.categoryid, t.categoryname
          from t_ues_pic_rescategory t
         start with t.categoryid = 27
        connect by prior t.categoryid = t.parentid) tp
 where r.categoryid = tp.categoryid
 order by r.uploadtime desc