Query output formatting

[Steven Wong]

I have this query to calculate some averages:

select hour, cdn, avg(bitrate) from fact_table group by hour, cdn
1              8              a
1              9              b
2              8              c
3              8              d
3              9              e

But I want the output to be in the following format so that it can be 
eyeballed/graphed more easily:

1              a              b
2              c              NULL
3              d             e

(The 2nd and 3rd columns are averages for cdn 8 and 9, respectively.)

Is there an easy way to do this - in Hive, Unix, etc.? Suggestions (or, better 
yet, solutions) are welcome.

I imagine a UDAF could do this (see below), but AFAIK it is not built into Hive.

select hour, some_udaf(abr, cdn, array(8, 9))
from (select hour, cdn, avg(bitrate) as abr from fact_table group by hour, cdn) 
t
group by hour

Thanks.
Steven