SELECT T.OWNER

     , T.TABLE_NAME

     , TC.COMMENTS

     , C.COLUMN_NAME

     , CC.COMMENTS

     , C.DATA_TYPE

     , C.DATA_LENGTH

  FROM ALL_TABLES T

     , ALL_TAB_COMMENTS TC

     , ALL_TAB_COLUMNS C

     , ALL_COL_COMMENTS CC

 WHERE T.TABLE_NAME = TC.TABLE_NAME

   AND T.TABLE_NAME = C.TABLE_NAME

   AND C.TABLE_NAME = CC.TABLE_NAME

   AND C.COLUMN_NAME = CC.COLUMN_NAME

   AND T.OWNER IN ('AAAA', 'BBBB')

 ORDER BY T.OWNER

        , T.TABLE_NAME

        , C.COLUMN_ID

;