Oracle中的rownum与DB2中的row_number()over()

select rownum , m.* from (select '汇总' as MENUNAMES,count(*) as NUMCOUNT from PEVENTRECORD where (EVENT='CLICK' OR EVENT = 'VIEW')

AND TO_CHAR(TRANSTIME,'yyyy-MM-dd') >= '2015-02-02' AND TO_CHAR(TRANSTIME,'yyyy-MM-dd') <= '2015-05-11'

union select EVENTKEY as MENUNAMES,count(*) as NUMCOUNT from PEVENTRECORD where (EVENT='CLICK' OR EVENT='VIEW')

AND TO_CHAR(TRANSTIME,'yyyy-MM-dd') >= '2015-02-02' AND TO_CHAR(TRANSTIME,'yyyy-MM-dd') <= '2015-05-11' group by EVENTKEY order by NUMCOUNT) m
怎么将这个sql改成DB2的sql啊？用row_number()over()代替的。谢谢 各位大牛！

 select rownum , m.* from 
 改成
 select  row_number() over(ORDER BY NUMCOUNT),m.* from