in select

UPDATE  mytable
SET     node_index = 0
WHERE   rowid IN
        (
        SELECT  rid
        FROM    (
                SELECT  rowid AS rid
                FROM    mytable
                WHERE   procs_dt IS NOT NULL
                ORDER BY
                        cret_dt, prty
                )
        WHERE   rownum <= 10
        )


update mytable set node_index=0 where id in (
    SELECT
        id
     FROM
        ( SELECT id FROM mytable WHERE procs_dt IS NULL order by CRET_DT,PRTY desc)
     WHERE
        rownum<=10
    )