Como obter dados de todos os níveis usando uma única consulta SQL para lista de materiais

CREATE TABLE table_name ( bom_code, rm_code, qty ) AS
  SELECT 'A', 'B', 1 FROM DUAL UNION ALL
  SELECT 'A', 'C', 2 FROM DUAL UNION ALL
  SELECT 'A', 'D', 5 FROM DUAL UNION ALL
  SELECT 'A', 'E', 3 FROM DUAL UNION ALL
  SELECT 'A', 'F', 8 FROM DUAL UNION ALL
  SELECT 'D', 'G', 2 FROM DUAL UNION ALL
  SELECT 'D', 'H', 1 FROM DUAL UNION ALL
  SELECT 'D', 'I', 1 FROM DUAL UNION ALL
  SELECT 'D', 'J', 1 FROM DUAL UNION ALL
  SELECT 'F', 'K', 1 FROM DUAL UNION ALL
  SELECT 'F', 'L', 1 FROM DUAL UNION ALL
  SELECT 'G', 'Z', 1 FROM DUAL UNION ALL
  SELECT 'G', 'AA', 3 FROM DUAL UNION ALL
  SELECT 'I', 'M', 4 FROM DUAL UNION ALL
  SELECT 'I', 'N', 9 FROM DUAL UNION ALL
  SELECT 'I', 'O', 7 FROM DUAL UNION ALL
  SELECT 'N', 'P', 6 FROM DUAL UNION ALL
  SELECT 'N', 'Q', 12 FROM DUAL UNION ALL
  SELECT 'N', 'R', 4 FROM DUAL UNION ALL
  SELECT 'N', 'S', 9 FROM DUAL UNION ALL
  SELECT 'S', 'T', 3 FROM DUAL UNION ALL
  SELECT 'S', 'U', 2 FROM DUAL UNION ALL
  SELECT 'T', 'V', 1 FROM DUAL UNION ALL
  SELECT 'T', 'W', 3 FROM DUAL UNION ALL
  SELECT 'U', 'X', 5 FROM DUAL UNION ALL
  SELECT 'U', 'Y', 8 FROM DUAL;

SELECT t.*,
       SYS_CONNECT_BY_PATH( BOM_CODE, '-' ) || '-' || RM_CODE AS path,
       LEVEL
FROM   table_name t
WHERE  CONNECT_BY_ISLEAF = 1
START WITH bom_code = 'A'
CONNECT BY PRIOR rm_code = bom_code;

SELECT t.*,
       SYS_CONNECT_BY_PATH( BOM_CODE, '-' ) || '-' || RM_CODE AS path,
       LEVEL,
       ( SELECT SUM( qty )
         FROM   table_name s
         START WITH t.rm_code = s.rm_code
         CONNECT BY PRIOR bom_code = rm_code ) AS total_qty
FROM   table_name t
WHERE  CONNECT_BY_ISLEAF = 1
START WITH bom_code = 'A'
CONNECT BY PRIOR rm_code = bom_code;