How to do Running Total in Netezza

Imagine the following table (called TestTable):

id     somedate    somevalue

--     --------    ---------

45     01/Jan/09   3

23     08/Jan/09   5

12     02/Feb/09   0

77     14/Feb/09   7

39     20/Feb/09   34

33     02/Mar/09   6

I would like a query that returns a running total in date order, like:

id     somedate    somevalue  runningtotal

--     --------    ---------  ------------

45     01/Jan/09   3          3

23     08/Jan/09   5          8

12     02/Feb/09   0          8

77     14/Feb/09   7          15  

39     20/Feb/09   34         49

33     02/Mar/09   6          55

Here is the netezza query to do it

SELECT 

ID,

somedate,

somevalue,

SUM(somevalue) OVER(PARTITION BY ID ORDER BY somedate ASC rows unbounded preceding) runningtotal

from

TestTable