최상위 부모 가져오기

            SELECT
                MAX(PRDLST_ID)KEEP(DENSE_RANK FIRST ORDER BY T_LEVEL DESC) INTO v_prod_prdlst_id
            FROM (
              SELECT PRDLST_ID, LEVEL T_LEVEL FROM TB_BOM
                START WITH PRDLST_ID = v_ml_prdlst_id
                CONNECT BY PRIOR PARNTS_PRDLST_ID = PRDLST_ID
              );