Oracle wmsys.wm_concat行列转换

select wmsys.wm_concat(T.PROD_KIND_NAME)
from (
select B.PROD_KIND_NAME,level  from MM_PRODUCTS_CATALOG b
start with PRODUCT_KIND_ID = 4
connect by  prior  PROD_KIND_PARENT_ID  =   PRODUCT_KIND_ID
order by level
) T