连接sql

select substr(sys_connect_by_path(v_param_name, ','), 2) a, a.*
from (select aa.*,
v_item_id || ',' || (rno + 1) rno1,
v_item_id || ',' || rno rno2
from (select v_item_id,
v_param_name,
row_number() over(partition by v_item_id order by n_param_id) rno,
row_number() over(partition by v_item_id order by n_param_id desc) flag
from tb_pu_parameter) aa) a
where flag = 1
connect by prior rno1 = rno2
start with rno = 1